ArsDigita, LLC, was a web development company founded in Cambridge, Massachusetts in 1997. The company produced a popular open source toolkit, the ArsDigita Community System (ACS), for building database-backed community websites, and flourished at the peak of the dot-com bubble. ACS was also the roots of OpenACS, which added PostgreSQL as a database option and gave the system a fully open-source stack.

Philip Greenspun is an American computer scientist, educator, early Internet entrepreneur, and pilot who was a pioneer in developing online communities like photo.net.