> - I use Twitter a LOT to communicate with people I'd otherwise have no access to, because I don't have their email or they are too busy answering me through the company mailbox. Twitter makes everyone (except for celebs) reachable. If I need some guy at Google who write library X, I just send him a tweet.

That one is a killer-feature right there I've managed to discover lately. Twitter completely sucks, because if you are just a normal person doing normal things noone will ever care about you. BUT, in case you're interested in some very specific topic and the contributing people then you should give twitter a try...