Don't ask me what exactly web 3.0 is, but Jason Vallery has a good summary of the International Conference on Weblogs and Social Media meeting held last week in Boulder, CO, where web 3.0 was discussed.  His summary:

"While the future is far from certain, one thing is for sure. The future of social media and “web 3.0″will be focused around two key areas. Mobility and search. Developers needs to come up with better ways to get at the information you need and make it simple to do from mobile devices. While some predict the death of sites like Twitter , I think they are ground-breakers in their field. When blogging can become a commodity that is approachable to anyone, and all of that data is well organized and searchable, that is when we can say that web 3.0 has arrived."

And if I had one thing to add: that the data/information sets from a search are all the more mash-able, i.e., in standard formats that enable users to easily mix and combine the data into new information structures and applications. Think Google Maps in 5 years.