Why Should I Twitter? Clue me in!

I signed up for Twitter quite awhile ago (to grab the user name "laurencooney") but I rarely use it. Recently I've had a lot of people (well, about 20) add me as someone they are following on Twitter. I'm not quite sure why, but I'm willing to take a stab at Twittering if someone can give me some good reasons to why I should use it... I get the part about following conversations, or asking questions that you need answered at that moment, and it *seems* like it might be convenient...

Can someone clue me in? Am I missing something here? I feel like the last person invited to the biggest party of the year... help! :) /LC