The live demo showed off some impressive features. By putting the social layer under its search engine, Bing can deliver very targeted results when it comes to searching for individual people. Say you're searching for a friend of a friend you met at a party, but are having trouble remembering exactly how you know them.
Bing will now use Facebook's vast network of social connections to personalize search. The search for that partygoer will deliver their Facebook page as well as the circle of people you know who are connected to the person. That lets would users pin down exactly how they know that person and provides a far deeper picture of the connections between them than a simple Google search would.
A search for a movie or a new album will return the friends in your Facebook network who have "Liked" this item or commented on it in some way. That is the kind of social reinforcement that holds a lot of appeal for advertisers.
Bing's market share growth has been tepid over the last few months while Google's has held steady. As Mark Zuckerberg said during today's live announcement, Facebook's social platform has powered phenomenal growth for gaming companies like Zynga. What excites Zuckerberg about the partnership is that Microsoft is the "clear underdog" in search. He believes that means Microsoft is willing to experiment and push the boundaries of what users are comfortable with. That's Zuckerberg's area of expertise.
If Microsoft lets Facebook guide the development of its social search products, expect Bing to become a much more formidable competitor to Google.
Image from Flickr user Aemde