- Flickr
- Delicious
- Google Reader
- Others
One solution is FriendFeed. Here's a FriendFeed widget with my recent activity:
You can subscribe to FriendFeed and add your friends. Of course, there's another step that can take some time. Facebook also has a FriendFeed application you can add. It will automatically add your Facebook friends to your FriendFeed as they sign up without your having to go through another step.
I find FriendFeed particularly useful professionally in regard to seeing what web sites my library colleagues are bookmarking in Delicious. And that's really what social networking is about - learning from your peers.