The image below is a screenshot of my facebook News Feed. It is basically my Facebook AttentStream. Mix in posts from your RSS reading list and the LifeStream of your friends who don't live on FaceBook and you're done.
The Facebook News Feed, to me, is one of their most impressive innovations. Among many things it encourages viral swarming of friends to given activities, applications and groups. I wish more applications provided one.
The goal of Particls: To provide an interface into which the status changes of your friends co-exist with the news headlines you care about in a unified, ranked and filtered river of news.
All we need now is an RSS feed of your Facebook News Feed.