Two releases on the same day for competing products in the virtual space arena has brought the topic to the forefront again.  Both Lively and Vivaty allow the user to insert a 3D room into a webpage.  Both are much simpler than SecondLife with limited creation capabilities.  Mostly users decorate their rooms, import media from the web, and text chat with other visitors.  Vivaty is tied to either AIM or Facebook with each account tied to your own "scene".