Markstein began the project during 1999 with several earlier titles: he changed Don's Cartoon Encyberpedia (1999) to Don Markstein's Cartoonopedia (2000) after learning the word "Encyberpedia" had been trademarked. During 2001, he settled on his final title, noting, "Decided (after thinking about it for several weeks) to change the name of the site to Don Markstein's Toonopedia, rather than Cartoonopedia. Better rhythm in the name, plus 'toon' is probably a more apt word, in modern parlance, than 'cartoon', for what I'm doing."