Bing Admits Using Customer Search Data

What part of search engines (and everyone else) using their customer's data to improve their service is news?

We get articles on HN most days on A/B testing and other things you can do to improve your performance, and I'm quite sure Google doesn't route my search results like this for nothing:

http :// www .google.com/url?sa=t&source=web&cd=1&ved=0CBIQFjAA&url=http%3A%2F%2Fwww.miniclip.com%2F&ei=KnRITbyhPIzQgAejqfmOBg&usg=AFQjCNHqQo9TrXtXXM5lDpiCmNQO9xwkhw