Reasons:

1) I like internet communities and discussions
2) I like posting anonymously and feeling safe
3) I don't know japanese so it's the best next thing I can get after 2ch.
4) I have no real life.
5) This forum will keep me busy killing my time before I discover a new "passion" that will also help me kill my time and help me get away from real life responsibilities, social life and generally live a life like a normal human...
6) I can finally say all those shit you just read to a bunch of people who will never really care just to have the illusion that I am actually talking to someone.