And also, it seems like lots of my LJ friends have disappeared too. About 10 or more of my friends have not posted for more than 2 weeks... Where is everyone? Is it because the weather's getting warmer, or because people are taking final exams? Or is everyone disappearing from LJ due to sites like facebook and twitter?

Guilty as charged! I've been spending a lot of time on Twitter lately. I have been forwarding my Twitters to LJ though. I've also been trying to keep up on reading my friends list on LJ, and I even comment when I have something to say!