Yesterday was a sad day because my favorite web comic, Girly, ended with its 764th page. I started reading it when it was at #123 (reading through from the beginning, of course). The comic is about a girl who starts following around another girl and declares her to be her sidekick. With some persistence, the reluctant sidekick agrees, and they have wacky adventures. It is both hilarious and epic at the same time. If you don’t go check it out, I will be forced to threaten you. Don’t make me threaten you.
Another notable web comic is xkcd.