Back in 2001 there were similar apporaches usually based on Java & browserbased with virtual chatrooms and possibilities virtual rooms (in 3d!) in which you could meet friends and strangers. It was a fun experience yet there was always a lack of content and limitations set by the environment. That also applies to environments such as world of warcraft or the mentioned second life.
It shows why the groundswell - a synonym spreaded by Forester for a movement in the internet ("independent" movement without the direct control by a few - ) is successful. Humans like to connect and share - especially when it is different from the general public or people will show you appreciation for sharing it.
For me this whole issue is more like living a second life - on the the web - not limited by frameworks but as the ability to access information, connect with people and manage virtual identities but with the direct life connection rather than playing and imitating a different environment.