Here's an interesting article on IBM's efforts to blend social software, identity, and the virtual world through Lotus.
IBM Lotus programmers and engineers from IBM's research groups are currently working on ways to employ virtual reality technologies with Lotus Connections social computing software, said Jeff Schick, vice president of social computing for IBM.
I heard someone describe the 3D web by saying 'people are back', and I think this is the true strength of environments like Second Life. It's not about the graphics or a particular virtual space, it's about the people and experiences that are available. Maintaining and monitoring a social network is Web2.0, the 3D web is about being present with friends and peers in meaningful ways, through virtual experiences.