Honestly, I’am not convinced that this integration would be very useful. Microsoft has a good point when says that people usually make decisions after consulting with friends, but I think people always will prefer to continue writing a little message, an email or giving a quick call to that friend to get the feedback. It is difficult for a search engine to become a substitute for human interaction.
I like more the +1 project from Google, is a less intrusive way to make the same social search idea works.
But, what do you think about Bing integration with Facebook?