clipped from: www.techcrunch.com   

Facebook has a new answer to the portal question. The “social graph,” or your network of relationships, will push information to you. You’ll learn from your friends. Thanks to Facebook’s new developer platform, the types of information being disseminated now include not just news, photos, events, and groups but also music, videos, books, movies, causes, political campaigns — and the list is rapidly growing into almost every conceivable category.

Not only Digg, but virtually all Web 2.0 applications which are based on the wisdom of crowds can be reconceived as Facebook apps based on the wisdom (or trust) of friends.
The potential for Facebook to layer on any feature whose value increases with the participation of friends is an incredibly broad canvas for a portal. Moreover, as each new application gains acceptance, it enriches the overall value of the network and makes it incrementally more likely that the next application will be tried.