Yahoo has this great post on Social Search. Guess what. it is a heck of a lot easier with Identity.

• The trusted web Anyone can save, tag, and share knowledge with their community.
• Personalized search My Web 2.0 is powered by Yahoo!'s new MyRank Search Technology, which provides personalized search results based on the shared knowledge of the people they trust.
• Control over what is shared and with whom Each page saved and tagged can be shared with the world, just with friends and their friends, or kept private.
• Structured tagging The internet is about much more than web pages - key dimensions like time and location can be as important as the content itself.
• Open APIs - Through the use of My Web 2.0's XML and RDF APIs , a whole host of new applications can be built - like what the folks in the Stanford University TAP project are working on.

http://www.ysearchblog.com/archives/000130.html