I did a search for 'data mining' on Bing, and was surprised to see the search results. I cut and pasted these search results at the bottom of my message.

To summarize:

• If you are logged in on Facebook, Microsoft will access your Facebook cookie, and retrieve and display customized search results about what your Facebook friends like (see below), blended with traditional generic search results.
• So Microsoft is not trying to compete with Google by improving search algorithms / search intelligence (both Google and Bing exhibit very similar flaws in search results). Instead it tries to compete by adding features (images, Facebook related stuff).
• Microsoft, despite being concerned by privacy issues and favoring browser-oriented "do not track" technology, is doing exactly the opposite, by exploiting Facebook cookies outside Facebook. Indeed, users are going to ask "How does Microsoft know that Gary is one of my Facebook friends?" The answer lies in the fact that Microsoft owns a big chunk of Facebook, and thus tries to leverage it, in particular on Bing.