Yahoo come out with it :

So I wonder what's the climate of opinion here? Do people think this will work?

I mean, I can see having smart people filtering search results will help eliminate spam and SEOs. But is this benefit likely to be outweighed by the "echo chamber" effects?

Sometimes I'm looking for something beyond what my friends already know. After all, if my friends know it, then I'm likely to already know it too. Might I find myself constrained in a bubble of things I and my friends are already familiar, with relevant but completely unknown results excluded to outer darkness?