I spent a lot of time online for two main reasons:

1.) I've always had this thing where I get nervous around people in real life... but I still crave social interaction on occasion. It's much easier for me to talk to people online. (I think it has to do with my anxiety issues.)

2.) I'm in an online relationship. My boyfriend is online. 'nuff said.

I imagine that I will probably be spending considerably less time online once my boyfriend and I are together in meatspace... but I will still be online quite a bit to talk to friends and hang out on forums and stuff. (And Neopets. Shhh, don't tell anybody!)