Computerworld had an article today about IBM updating its research image. Included in that was a link to some work IBM has done with Second Life and Computer City in creating a 3D online store. When executives talked about Second Life during the Lotusphere 2007 OGS I was admittedly skeptical. I'm still not convinced there's much meat on that bone for business end users, but it could be interesting for B2C interactions.
While this is going on Microsoft hasn't been standing still. They recently recently launched WinFX as .Net 3.0 and Avalon as Windows Presentation Framework (WPF). Together these allow developers to code web sites that do both 2D and 3D rendering on the Internet, and they also have people working on 3D stores. They also have another set of technologies to provide 3D visualization on the Internet using spatial mapping. If you haven't seen it yet, check out Photosynth.
I don't know where any of this might lead but it is very, very interesting.