Its the one thing on the internet that, since joining, I have been persistently on. No games, other sites, or even email services have been able to do that.
I'm on every day, mostly as something to look at when I'm distracted when making digital art. Its the IRC that gets me- I love talking to the people there and skype with 'em when I can.
I don't suppose its comparative to an addiction because it doesn't interfere with my daily routine, but I have put a lot of time into here.
Also, Tenmarrrrrrrrrrrrrr!