Munroe had originally used xkcd as an instant messaging screenname because he wanted a name without a meaning so he would not eventually grow tired of it. He registered the domain name, but left it idle until he started posting his drawings, perhaps in September 2005. The webcomic quickly became very popular, garnering up to 70 million hits a month by October 2007. Munroe has said, "I think the comic that's gotten me the most feedback is actually the one about the stoplights".