Google can drive traffic to small Web sites with friendconnect. A preview of the system will be available later today. The service should start in a couple of months.
You can see how friendconnect works in a video on Google.
Google gives a pretty good picture with an example from Ingrid Michaelson. According to Google, "visitors will be able to see comments by friends from their social networks, add music to their profiles, see who is attending concerts, and enjoy other features of the iLike application, all at Ingrid's website."
Friendconnect is also highlighted on the New York Times blog.