If you need to get things off your mind, but cant seem to be able to say it in person to another human, then check these out:

Twitter is similar to Pownce is similar to Jaiku is similar to Tumblr as Profilactic is similar to Socialthing is similar to BrightKite is similar to FriendFeed as Scribblelive is similar to CoveritLive as Virb is similar to Trig is similar to my.9rules. That is hardly even touching everything that is out there now. You can even incorporate a lot of these directly in your browser - if you download the social browser Flock.