Yeah, and I'm probably on it way too much. It pretty much has replaced any instant messaging client; if they integrate Skype-like services it will pretty much become the new standard for online communication of any form.
If you follow bands and such you get a lot of great perks (the Homefront soundtrack is free to download for a limited time, for example), and it's a good way to keep up with friends or just to kill boredom.
I'm not surprised most people here hate it, but honestly, it's just kinda there for fun. Use it if you want.