An excerpt from Microsoft’s response to Google’s cheating accusation
We use over 1,000 different signals and features in our ranking algorithm. A small piece of that is clickstream data we get from some of our customers, who opt-in to sharing anonymous data as they navigate the web in order to help us improve the experience for all users.
To be clear, we learn from all of our customers. What we saw in today’s story was a spy-novelesque stunt to generate extreme outliers in tail query ranking. It was a creative tactic by a competitor, and we’ll take it as a back-handed compliment. But it doesn’t accurately portray how we use opt-in customer data as one of many inputs to help improve our user experience.