A compelling post on the side of Bing.

By choosing gibberish search terms that produced no natural results, Google effectively eliminated all other factors that could have influenced Bing's rankings. The terms were found on none of the pages in the index and certainly aren't used in any links pointing to any sites. So when Google engineers suddenly provided a data point (the click data collected via the Bing toolbar) for Bing to latch onto, it's no surprise that even a minor factor was able to influence 9% of the rankings. There are a couple of points that are very important to establish at this point. First, ranking the same site #1 for any given query doesn't mean Bing is "copying" Google's results.

Second, the data being collected does NOT belong to Google. Yes, the data is being collected when the user is visiting Google, however, the users opted to provide their use data to Bing. Bing didn't somehow hack into Google's data, and Bing didn't scrape Google's search result page. Bing used data provided by their users to influence their rankings, which is a practice they've readily admitted is in use.