Google has launched Lively, a 3D social network! At first glance it looks like Second Life, but SL is all virtual. In Lively, everything besides the graphics is real, from the IM's to the chat rooms and individual web pages.
You enter a Lively room that is embedded on a blog or website and then immediately become emmersed in the room of the creator, engaging in his/her interests and passions.
For the time being, it's just available for Windows. It's still in Beta and is suffering a little from slow performance. The possibilities for this to just blow apart the social network world is staggering.