Augmented reality is an interactive experience of a real-world environment where the objects that reside in the real-world are "augmented" by computer-generated perceptual information, sometimes across multiple sensory modalities, including visual, haptic and olfactory. The overlaid sensory information can be constructive or destructive and is seamlessly interwoven with the physical world such that it is perceived as an immersive aspect of the real environment. In this way, augmented reality alters one's ongoing perception of a real-world environment, whereas virtual reality replaces the user's real-world environment with a simulated one. Augmented reality is related to two synonymous terms: mixed reality and computer-mediated reality; the primary value of augmented reality is that it brings components of the digital world into a person's perception of the real world, does so not as a simple display of data, but through the integration of immersive sensations that are perceived as natural parts of an environment.
The first functional AR systems that provided immersive mixed reality experiences for users were invented in the early 1990s, starting with the Virtual Fixtures system developed at the U. S. Air Force's Armstrong Laboratory in 1992; the first commercial augmented reality experiences were used in the entertainment and gaming businesses, but now other industries are getting interested about AR's possibilities for example in knowledge sharing, managing the information flood and organizing distant meetings. Augmented reality is transforming the world of education, where content may be accessed by scanning or viewing an image with a mobile device or by bringing immersive, markerless AR experiences to the classroom. Another example is an AR helmet for construction workers which display information about the construction sites. Augmented reality is used to enhance natural environments or situations and offer perceptually enriched experiences. With the help of advanced AR technologies the information about the surrounding real world of the user becomes interactive and digitally manipulable.
Information about the environment and its objects is overlaid on the real world. This information can be virtual or real, e.g. seeing other real sensed or measured information such as electromagnetic radio waves overlaid in exact alignment with where they are in space. Augmented reality has a lot of potential in the gathering and sharing of tacit knowledge. Augmentation techniques are performed in real time and in semantic context with environmental elements. Immersive perceptual information is sometimes combined with supplemental information like scores over a live video feed of a sporting event; this heads up display technology. Hardware components for augmented reality are: processor, display and input devices. Modern mobile computing devices like smartphones and tablet computers contain these elements which include a camera and MEMS sensors such as accelerometer, GPS, solid state compass, making them suitable AR platforms. There are 2 technologies: diffractive reflective waveguides. Augmented reality systems guru Karl Guttag compared the optics of diffractive waveguides against the competing technology, reflective waveguides.
Various technologies are used in augmented reality rendering, including optical projection systems, handheld devices, display systems worn on the human body. A head-mounted display is a display device worn on the forehead, such as helmet. HMDs place images of both virtual objects over the user's field of view. Modern HMDs employ sensors for six degrees of freedom monitoring that allow the system to align virtual information to the physical world and adjust accordingly with the user's head movements. HMDs can provide VR users with collaborative experiences. Specific providers, such as uSens and Gestigon, include gesture controls for full virtual immersion. In January 2015, Meta launched a project led by Horizons Ventures, Tim Draper, Alexis Ohanian, BOE Optoelectronics and Garry Tan. On February 17, 2016, Meta announced their second-generation product at TED, Meta 2; the Meta 2 head-mounted display headset uses a sensory array for hand interactions and positional tracking, visual field view of 90 degrees, resolution display of 2560 x 1440, considered the largest field of view available.
AR displays can be rendered on devices resembling eyeglasses. Versions include eyewear that employs cameras to intercept the real world view and re-display its augmented view through the eyepieces and devices in which the AR imagery is projected through or reflected off the surfaces of the eyewear's lenspieces. A head-up display is a transparent display that presents data without requiring users to look away from their usual viewpoints. A precursor technology to augmented reality, heads-up displays were first developed for pilots in the 1950s, projecting simple flight data into their line of sight, thereby enabling them to keep their "heads up" and not look down at the instruments. Near-eye augmented reality devices can be used as portable head-up displays as they can show data and images while the user views the real world. Many definitions of augmented reality only define it as overlaying the information; this is what a head-up display does.
A social network is a social structure made up of a set of social actors, sets of dyadic ties, other social interactions between actors. The social network perspective provides a set of methods for analyzing the structure of whole social entities as well as a variety of theories explaining the patterns observed in these structures; the study of these structures uses social network analysis to identify local and global patterns, locate influential entities, examine network dynamics. Social networks and the analysis of them is an inherently interdisciplinary academic field which emerged from social psychology, sociology and graph theory. Georg Simmel authored early structural theories in sociology emphasizing the dynamics of triads and "web of group affiliations". Jacob Moreno is credited with developing the first sociograms in the 1930s to study interpersonal relationships; these approaches were mathematically formalized in the 1950s and theories and methods of social networks became pervasive in the social and behavioral sciences by the 1980s.
Social network analysis is now one of the major paradigms in contemporary sociology, is employed in a number of other social and formal sciences. Together with other complex networks, it forms part of the nascent field of network science; the social network is a theoretical construct useful in the social sciences to study relationships between individuals, organizations, or entire societies. The term is used to describe a social structure determined by such interactions; the ties through which any given social unit connects represent the convergence of the various social contacts of that unit. This theoretical approach is relational. An axiom of the social network approach to understanding social interaction is that social phenomena should be conceived and investigated through the properties of relations between and within units, instead of the properties of these units themselves. Thus, one common criticism of social network theory is that individual agency is ignored although this may not be the case in practice.
Because many different types of relations, singular or in combination, form these network configurations, network analytics are useful to a broad range of research enterprises. In social science, these fields of study include, but are not limited to anthropology, communication studies, geography, information science, organizational studies, social psychology and sociolinguistics. In the late 1890s, both Émile Durkheim and Ferdinand Tönnies foreshadowed the idea of social networks in their theories and research of social groups. Tönnies argued that social groups can exist as personal and direct social ties that either link individuals who share values and belief or impersonal and instrumental social links. Durkheim gave a non-individualistic explanation of social facts, arguing that social phenomena arise when interacting individuals constitute a reality that can no longer be accounted for in terms of the properties of individual actors. Georg Simmel, writing at the turn of the twentieth century, pointed to the nature of networks and the effect of network size on interaction and examined the likelihood of interaction in loosely knit networks rather than groups.
Major developments in the field can be seen in the 1930s by several groups in psychology and mathematics working independently. In psychology, in the 1930s, Jacob L. Moreno began systematic recording and analysis of social interaction in small groups classrooms and work groups. In anthropology, the foundation for social network theory is the theoretical and ethnographic work of Bronislaw Malinowski, Alfred Radcliffe-Brown, Claude Lévi-Strauss. A group of social anthropologists associated with Max Gluckman and the Manchester School, including John A. Barnes, J. Clyde Mitchell and Elizabeth Bott Spillius are credited with performing some of the first fieldwork from which network analyses were performed, investigating community networks in southern Africa and the United Kingdom. Concomitantly, British anthropologist S. F. Nadel codified a theory of social structure, influential in network analysis. In sociology, the early work of Talcott Parsons set the stage for taking a relational approach to understanding social structure.
Drawing upon Parsons' theory, the work of sociologist Peter Blau provides a strong impetus for analyzing the relational ties of social units with his work on social exchange theory. By the 1970s, a growing number of scholars worked to combine the different traditions. One group consisted of sociologist Harrison White and his students at the Harvard University Department of Social Relations. Independently active in the Harvard Social Relations department at the time were Charles Tilly, who focused on networks in political and community sociology and social movements, Stanley Milgram, who developed the "six degrees of separation" thesis. Mark Granovetter and Barry Wellman are among the former students of White who elaborated and championed the analysis of social networks. Beginning in the late 1990s, social network analysis experienced work by sociologists, political scientists, physicists such as Duncan J. Watts, Albert-László Barabási, Peter Bearman, Nicholas A. Christakis, James H. Fowler, others and applying new models and methods to emerging data available about online social networks, as well as "digital traces" regarding face-to-face networks.
In general, social networks are self-organizing, em
Wikipedia is a multilingual online encyclopedia with free content and no ads, based on open collaboration through a model of content edit by web-based applications like web browsers, called wiki. It is the largest and most popular general reference work on the World Wide Web, is one of the most popular websites by Alexa rank as of April 2019, it is owned and supported by the Wikimedia Foundation, a non-profit organization that operates on money it receives from donors to remain ad free. Wikipedia was launched on January 2001, by Jimmy Wales and Larry Sanger. Sanger coined its name, as a portmanteau of wiki and "encyclopedia". An English-language encyclopedia, versions in other languages were developed. With 5,838,942 articles, the English Wikipedia is the largest of the more than 290 Wikipedia encyclopedias. Overall, Wikipedia comprises more than 40 million articles in 301 different languages and by February 2014 it had reached 18 billion page views and nearly 500 million unique visitors per month.
In 2005, Nature published a peer review comparing 42 hard science articles from Encyclopædia Britannica and Wikipedia and found that Wikipedia's level of accuracy approached that of Britannica, although critics suggested that it might not have fared so well in a similar study of a random sampling of all articles or one focused on social science or contentious social issues. The following year, Time magazine stated that the open-door policy of allowing anyone to edit had made Wikipedia the biggest and the best encyclopedia in the world, was a testament to the vision of Jimmy Wales. Wikipedia has been criticized for exhibiting systemic bias, for presenting a mixture of "truths, half truths, some falsehoods", for being subject to manipulation and spin in controversial topics. In 2017, Facebook announced that it would help readers detect fake news by suitable links to Wikipedia articles. YouTube announced a similar plan in 2018. Other collaborative online encyclopedias were attempted before Wikipedia, but none were as successful.
Wikipedia began as a complementary project for Nupedia, a free online English-language encyclopedia project whose articles were written by experts and reviewed under a formal process. It was founded on March 2000, under the ownership of Bomis, a web portal company, its main figures were Bomis CEO Jimmy Wales and Larry Sanger, editor-in-chief for Nupedia and Wikipedia. Nupedia was licensed under its own Nupedia Open Content License, but before Wikipedia was founded, Nupedia switched to the GNU Free Documentation License at the urging of Richard Stallman. Wales is credited with defining the goal of making a publicly editable encyclopedia, while Sanger is credited with the strategy of using a wiki to reach that goal. On January 10, 2001, Sanger proposed on the Nupedia mailing list to create a wiki as a "feeder" project for Nupedia; the domains wikipedia.com and wikipedia.org were registered on January 12, 2001 and January 13, 2001 and Wikipedia was launched on January 15, 2001, as a single English-language edition at www.wikipedia.com, announced by Sanger on the Nupedia mailing list.
Wikipedia's policy of "neutral point-of-view" was codified in its first months. Otherwise, there were few rules and Wikipedia operated independently of Nupedia. Bomis intended to make Wikipedia a business for profit. Wikipedia gained early contributors from Nupedia, Slashdot postings, web search engine indexing. Language editions were created, with a total of 161 by the end of 2004. Nupedia and Wikipedia coexisted until the former's servers were taken down permanently in 2003, its text was incorporated into Wikipedia; the English Wikipedia passed the mark of two million articles on September 9, 2007, making it the largest encyclopedia assembled, surpassing the 1408 Yongle Encyclopedia, which had held the record for 600 years. Citing fears of commercial advertising and lack of control in Wikipedia, users of the Spanish Wikipedia forked from Wikipedia to create the Enciclopedia Libre in February 2002; these moves encouraged Wales to announce that Wikipedia would not display advertisements, to change Wikipedia's domain from wikipedia.com to wikipedia.org.
Though the English Wikipedia reached three million articles in August 2009, the growth of the edition, in terms of the numbers of new articles and of contributors, appears to have peaked around early 2007. Around 1,800 articles were added daily to the encyclopedia in 2006. A team at the Palo Alto Research Center attributed this slowing of growth to the project's increasing exclusivity and resistance to change. Others suggest that the growth is flattening because articles that could be called "low-hanging fruit"—topics that merit an article—have been created and built up extensively. In November 2009, a researcher at the Rey Juan Carlos University in Madrid found that the English Wikipedia had lost 49,000 editors during the first three months of 2009; the Wall Street Journal cited the array of rules applied to editing and disputes related to such content among the reasons for this trend. Wales disputed these claims in 2009, denying the decline and questioning the methodology of the study. Two years in 2011, Wales acknowledged the presence of a slight decline, noting a decrease from "a little more than 36,000 writers" in June 2010 to 35,800 in June 2011.
In the same interview, Wales claimed the number of editors was "stable and sustainable". A 2013 article titled; the article revealed
Cyberbullying or cyberharassment is a form of bullying or harassment using electronic means. Cyberbullying and cyberharassment are known as online bullying, it has become common among teenagers. Cyberbullying is when someone teens, bully or harass others on social media sites. Harmful bullying behavior can include posting rumors, sexual remarks, a victims' personal information, or pejorative labels. Bullying or harassment can be identified by an intent to harm. Victims may have lower self-esteem, increased suicidal ideation, a variety of emotional responses, including being scared, frustrated and depressed. Awareness in the United States has risen in the 2010s, due in part to high-profile cases. Several US states and other countries have laws specific to cyberbullying; some are designed to target teen cyberbullying, while others use laws extending from the scope of physical harassment. In cases of adult cyberharassment, these reports are filed beginning with local police. Research has demonstrated a number of serious consequences of cyberbullying victimization.
Internet trolling is a common form of bullying over the Internet in an online community in order to elicit a reaction, disruption, or for someone's own personal amusement. Cyberstalking is another form of bullying or harassment that uses electronic communications to stalk a victim. Not all negative interaction on social media can be attributed to cyberbullying. Research suggests that there are interactions online that result in peer pressure, which can have a negative, positive, or neutral impact on those involved. A used definition of cyberbullying is "an aggressive, intentional act or behavior, carried out by a group or an individual, using electronic forms of contact and over time against a victim who cannot defend him or herself." There are many variations of the definition, such as the National Crime Prevention Council's more specific definition: "the process of using the Internet, cell phones or other devices to send or post text or images intended to hurt or embarrass another person."Cyberbullying is similar to traditional bullying, with some notable distinctions.
Victims of cyberbullying may not know the identity of their bully, or why the bully is targeting them. The harassment can have wide-reaching effects on the victim, as the content used to harass the victim can be spread and shared among many people and remains accessible long after the initial incident; the terms "cyberharassment" and "cyberbullying" are sometimes used synonymously, though some people use the latter to refer to harassment among minors or in a school setting. Cyberstalking is a form of online harassment in which the perpetrator uses electronic communications to stalk a victim; this is considered more dangerous than other forms of cyberbullying because it involves a credible threat to the victim's safety. Cyberstalkers may send repeated messages intended to harass, they may encourage others to do the same, either explicitly or by impersonating their victim and asking others to contact them. Internet trolls intentionally try to offend others in order to elicit a reaction. Trolls and cyberbullies do not always have the same goals: while some trolls engage in cyberbullying, others may be engaged in comparatively harmless mischief.
A troll may be disruptive either for their own amusement or because they are genuinely a combative person. Manuals to educate the public and parents summarize, "Cyberbullying is being cruel to others by sending or posting harmful material using a cell phone or the internet." Research and education in the field are ongoing. Research has identified basic definitions and guidelines to help recognize and cope with what is regarded as abuse of electronic communications. Cyberbullying involves repeated behavior with intent to harm. Cyberbullying is perpetrated through harassment, denigration and exclusion Cyberbullying can be as simple as continuing to send emails or text messages harassing someone who has said they want no further contact with the sender, it may include public actions such as repeated threats, sexual remarks, pejorative labels or defamatory false accusations, ganging up on a victim by making the person the subject of ridicule in online forums, hacking into or vandalizing sites about a person, posting false statements as fact aimed a discrediting or humiliating a targeted person.
Cyberbullying could be limited to posting rumors about a person on the internet with the intention of bringing about hatred in others' minds or convincing others to dislike or participate in online denigration of a target. It may go to the extent of identifying victims of crime and publishing materials defaming or humiliating them. Cyberbullies may disclose victims' personal data on websites or forums—called doxing, or may use impersonation, creating fake accounts, comments or sites posing as their target for the purpose of publishing material in their name that defames, discredits or ridicules them; this can leave the cyberbully anonymous, which can make it difficult for them to be caught or punished for their behavior, although not all cyberbullies maintain their anonymity. Text or instant messages and emails between friends can constitute cyberbullying if what is said is hurtful; the recent rise of smartphones and mobi
Facebook, Inc. is an American online social media and social networking service company. It is based in California, it was founded by Mark Zuckerberg, along with fellow Harvard College students and roommates Eduardo Saverin, Andrew McCollum, Dustin Moskovitz and Chris Hughes. It is considered one of the Big Four technology companies along with Amazon and Google; the founders limited the website's membership to Harvard students and subsequently Columbia and Yale students. Membership was expanded to the remaining Ivy League schools, MIT, higher education institutions in the Boston area. Facebook added support for students at various other universities, to high school students. Since 2006, anyone who claims to be at least 13 years old has been allowed to become a registered user of Facebook, though variations exist in this requirement, depending on local laws; the name comes from the face book directories given to American university students. Facebook held its initial public offering in February 2012, valuing the company at $104 billion, the largest valuation to date for a newly listed public company.
It began selling stock to the public three months later. Facebook makes most of its revenue from advertisements; the Facebook service can be accessed from devices with Internet connectivity, such as personal computers and smartphones. After registering, users can create a customized profile revealing information about themselves. Users can post text and multimedia of their own devising and share it with other users as "friends". Users can use various embedded apps, receive notifications of their friends' activities. Users may join common-interest groups. Facebook had more than 2.3 billion monthly active users as of December 2018. It receives prominent media coverage, including many controversies such as user privacy and psychological effects; the company has faced intense pressure over censorship and over content that some users find objectionable. Facebook offers other services, it independently developed Facebook Messenger. Zuckerberg built; the site was comparable to Hot or Not and used "photos compiled from the online facebooks of nine Houses, placing two next to each other at a time and asking users to choose the "hotter" person".
Facemash attracted 22,000 photo-views in its first four hours. The site was sent to several campus group list-servers, but was shut down a few days by Harvard administration. Zuckerberg faced expulsion and was charged with breaching security, violating copyrights and violating individual privacy; the charges were dropped. Zuckerberg expanded on this project that semester by creating a social study tool ahead of an art history final exam, he uploaded all art images to a website, each of, accompanied by a comments section shared the site with his classmates. A "face book" is a student directory featuring personal information. In 2003, Harvard had only a paper version along with private online directories. Zuckerberg told the Crimson, "Everyone's been talking a lot about a universal face book within Harvard.... I think. I can do it better than they can, I can do it in a week." In January 2004, Zuckerberg coded a new website, known as "TheFacebook", inspired by a Crimson editorial about Facemash, stating, "It is clear that the technology needed to create a centralized Website is available... the benefits are many."
Zuckerberg met with Harvard student Eduardo Saverin, each of them agreed to invest $1,000 in the site. On February 4, 2004, Zuckerberg launched "TheFacebook" located at thefacebook.com. Six days after the site launched, Harvard seniors Cameron Winklevoss, Tyler Winklevoss, Divya Narendra accused Zuckerberg of intentionally misleading them into believing that he would help them build a social network called HarvardConnection.com. They claimed; the three complained to the Crimson and the newspaper began an investigation. They sued Zuckerberg, settling in 2008 for 1.2 million shares. Membership was restricted to students of Harvard College. Within a month, more than half the undergraduates had registered. Dustin Moskovitz, Andrew McCollum, Chris Hughes joined Zuckerberg to help manage the growth of the website. In March 2004, Facebook expanded to Columbia and Yale. and to all Ivy League colleges, Boston University, New York University, MIT, Washington and successively most universities in the United States and Canada.
In mid-2004, Napster co-founder and entrepreneur Sean Parker—an informal advisor to Zuckerberg—became company president. In June 2004, the company moved to California, it received its first investment that month from PayPal co-founder Peter Thiel. In 2005, the company dropped "the" from its name after purchasing the domain name facebook.com for US$200,000. The domain had belonged to AboutFace Corporation. In May 2005, Accel Partners invested $12.7 million in Facebook, Jim Breyer added $1 million of his own money. A high-school version of the site launched in September 2005. Eligibility expanded to include employees including Apple Inc. and Microsoft. On September 26, 2006, Facebook opened to everyone at least 13 years old with a valid email address. By late 2007, Facebook had 100,000 pages. Organization pages began rolling out in May 2009. On October 24, 2007, Microsoft announced th
Social networking service
A social networking service is an online platform which people use to build social networks or social relations with other people who share similar personal or career interests, backgrounds or real-life connections. The social network is distributed across various computer networks; the social networks are inherently computer networks, linking people and knowledge. Social networking services vary in the number of features, they can incorporate a range of new information and communication tools, operating on desktops and on laptops, on mobile devices such as tablet computers and smartphones. They may feature "web logging" diary entries online. Online community services are sometimes considered social-network services by programmers and users, though in a broader sense, a social-network service provides an individual-centered service whereas online community services are group-centered. Defined as "websites that facilitate the building of a network of contacts in order to exchange various types of content online," social networking sites provide a space for interaction to continue beyond in person interactions.
These computer mediated interactions link members of various networks and may help to both maintain and develop new social ties. Social networking sites allow users to share ideas, digital photos and videos, to inform others about online or real-world activities and events with people in their network. While in-person social networking – such as gathering in a village market to talk about events – has existed since the earliest development of towns, the Web enables people to connect with others who live in different locations, ranging from across a city to across the world. Depending on the social media platform, members may be able to contact any other member. In other cases, members can contact anyone they have a connection to, subsequently anyone that contact has a connection to, so on; the success of social networking services can be seen in their dominance in society today, with Facebook having a massive 2.13 billion active monthly users and an average of 1.4 billion daily active users in 2017.
LinkedIn, a career-oriented social-networking service requires that a member know another member in real life before they contact them online. Some services require members to have a preexisting connection to contact other members; the main types of social networking services contain category places, means to connect with friends, a recommendation system linked to trust. One can categorize social-network services into three types: socializing social network services used for socializing with existing friends online social networks are decentralized and distributed computer networks where users communicate with each other through internet services. Networking social network services used for non-social interpersonal communication social navigation social network services used for helping users to find specific information or resources There have been attempts to standardize these services to avoid the need to duplicate entries of friends and interests. A study reveals that India recorded world's largest growth in terms of social media users in 2013.
A 2013 survey found that 73% of U. S. adults use social-networking sites. There is a variety of social networking services available online. However, most incorporate common features: social networking services are Web 2.0, Internet-based applications user-generated content is the lifeblood of social networking services. Users create service-specific profiles for the site or app that are designed and maintained by the SNS organization social networking services facilitate the development of online social networks by connecting a user's profile with those of other individuals or groups; the variety and evolving range of stand-alone and built-in social networking services in the online space introduces a challenge of definition. Furthermore, the idea that these services are defined by their ability to bring people together and provides too broad a definition; such a broad definition would suggest that the telegraph and telephone were social networking services – not the Internet technologies scholars are intending to describe.
The terminology is unclear, with some referring to social networking services as social media. A recent attempt at providing a clear definition reviewed the prominent literature in the area and identified four commonalities unique to current social networking services: social networking services are interactive Web 2.0 Internet-based applications, user-generated content, such as user-submitted digital photos, text posts, "tagging", online comments, diary-style "web logs", is the lifeblood of the SNS organism, users create service-specific profiles for the site or app that are designed and maintained by the SNS organization, social networking services facilitate the development of social networks online by connecting a user's profile with those of other individuals or groups. The potential for computer networking to facilitate newly improved forms of computer-mediated social interaction was suggested early on. Efforts to support social networks via computer-mediated communication were made in many early online services, including Usenet, ARPANET, LISTSERV, bulletin board services.
Many prototypical features of social networking sites were present in online services such as America Online, CompuServe, ChatNet, The WELL. Early social netw
A wiki is a website on which users collaboratively modify content and structure directly from the web browser. In a typical wiki, text is written using a simplified markup language and edited with the help of a rich-text editor. A wiki is run using wiki software, otherwise known as a wiki engine. A wiki engine is a type of content management system, but it differs from most other such systems, including blog software, in that the content is created without any defined owner or leader, wikis have little inherent structure, allowing structure to emerge according to the needs of the users. There are dozens of different wiki engines in use, both standalone and part of other software, such as bug tracking systems; some wiki engines are open source. Some permit control over different functions. Others may permit access without enforcing access control. Other rules may be imposed to organize content; the online encyclopedia project Wikipedia is the most popular wiki-based website, is one of the most viewed sites in the world, having been ranked in the top ten since 2007.
Wikipedia is not a single wiki but rather a collection of hundreds of wikis, with each one pertaining to a specific language. In addition to Wikipedia, there are tens of thousands of other wikis in use, both public and private, including wikis functioning as knowledge management resources, notetaking tools, community websites, intranets; the English-language Wikipedia has the largest collection of articles. Ward Cunningham, the developer of the first wiki software, WikiWikiWeb described wiki as "the simplest online database that could work". "Wiki" is a Hawaiian word meaning "quick". Ward Cunningham and co-author Bo Leuf, in their book The Wiki Way: Quick Collaboration on the Web, described the essence of the Wiki concept as follows: A wiki invites all users—not just experts—to edit any page or to create new pages within the wiki Web site, using only a standard "plain-vanilla" Web browser without any extra add-ons. Wiki promotes meaningful topic associations between different pages by making page link creation intuitively easy and showing whether an intended target page exists or not.
A wiki is not a crafted site created by experts and professional writers, designed for casual visitors. Instead, it seeks to involve the typical visitor/user in an ongoing process of creation and collaboration that changes the website landscape. A wiki enables communities of contributors to write documents collaboratively. All that people require to contribute is a computer, Internet access, a web browser, a basic understanding of a simple markup language. A single page in a wiki website is referred to as a "wiki page", while the entire collection of pages, which are well-interconnected by hyperlinks, is "the wiki". A wiki is a database for creating and searching through information. A wiki allows non-linear, evolving and networked text, while allowing for editor argument and interaction regarding the content and formatting. A defining characteristic of wiki technology is the ease with which pages can be created and updated. There is no review by a moderator or gatekeeper before modifications are accepted and thus lead to changes on the website.
Many wikis are open to alteration by the general public without requiring registration of user accounts. Many edits can be made in real-time and appear instantly online, but this feature facilitates abuse of the system. Private wiki servers require user authentication to edit pages, sometimes to read them. Maged N. Kamel Boulos, Cito Maramba, Steve Wheeler write that the open wikis produce a process of Social Darwinism. "'Unfit' sentences and sections are ruthlessly culled and replaced if they are not considered'fit', which results in the evolution of a higher quality and more relevant page. While such openness may invite'vandalism' and the posting of untrue information, this same openness makes it possible to correct or restore a'quality' wiki page." Some wikis have an Edit button or link directly on the page being viewed, if the user has permission to edit the page. This can lead to a text-based editing page where participants can structure and format wiki pages with a simplified markup language, sometimes known as Wikitext, Wiki markup or Wikicode.
An example of this is the VisualEditor on Wikipedia. WYSIWYG controls do not, always provide