Thinking of Yahoo, why in the world doesn't Yahoo push Flickr as a social network? They certainly have all the tools in place (photo, video, users, groups, ads) that have always been superior to FaceBook.
Personally, I think Flickr could put FB to shame. Maybe the die hard photo fans wouldn't like it, but if you want to push advertising revenue I think they have a gold mine.
Yahoo! Anyone there listening?