Hey Umair, I've been working on this for about 2 years now. We're running in private alpha. We roll into beta early next year. It's hacking advertising into a person-to-person recommendation network.

Let me know if you want to see the private alpha.
 

I was just talking with the guys at www.loudervoice.com during the week, and they are very much into this way of doing things. Expect a fb release soon. HOWEVER: one of the things that might be interesting is if fb pushed recommendations from both strong and weak relationships to you, based on your conversations you were in. The mini-feed is not really "optional" yet it is undoubtedly powerful. You can tweak it, but it isn't "plastic/liquid" (maybe it should be!). For a lot of users out there, some push elements have value.
 

Hmmm...I could see this as being the "killer app" for OpenSocial. The same service that leverages all of a person's networks.
 

Now that's a smart idea from james right there....
 

And Simon.... , perhaps a great opportunity for someone to get in early and post an open API...