Esther Grace Earl was an American author, internet vlogger, online personality, and Nerdfighter, as well as an activist in the Harry Potter Alliance. Prior to her death from cancer in 2010, Earl befriended author John Green, who credited her for the inspiration to complete his bestselling 2012 novel The Fault in Our Stars. In 2014, Earl's writings were compiled with her biography This Star Won't Go Out, which appeared on the New York Times bestseller list for young adult books. Earl has been cited as an influential activist, with her family and online followers continuing to hold charity and fundraising events in her memory.

Nerdfighteria is a mainly online-based community subculture that originated on YouTube in 2007, when the VlogBrothers rose to prominence in the YouTube community. As their popularity grew, so did coverage on Nerdfighteria, whose followers are individually known as Nerdfighters. The term was coined when John saw a copy of the arcade game Aero Fighters and misread the title as Nerd Fighters.