Newsweek has an article next week called "What You Like" (with a short quote from yours truly) which describes the melding of a search engines with SNS functionality. I think we'll start to see elements of an SNS in all sorts of applications.
In other news, the ENISA position paper on Security Issues and Recommendations for Online Network Sites is now out. This was a large collaboration with all the benefits and problems typical of these ventures. Of course, I have a range of feelings about the recommendations and some I see as less necessary than others. But overall I am hoping this will be useful is helping folks think about the design and use of these sites.