Although I've used the term myself, I'm coming around to the point of view that there won't be any "web 3.0" that is "about" any one thing. OpenID/data portability, semantics, the mobile web... there are too many developments that could "be" the next iteration of the web. I'd really like it if the mobile/location-contextual web became the next collective web explosion, but I don't think any one thing will dominate.