The idea presented implicates that the Bing search engine servers were sending queries to Google search engine servers and storing the results. But that's not what happened, even in the article you linked to. What happened there is that users who had the Bing toolbar, and opted in to have their behavior tracked, did have an influence on the Bing search engine. Given that's the point of the opt in behavior, that's no surprised. And it had nothing to do with Google. The Bing toolbar was looking for situations where a user would enter text into a text box, and then click on a link. It didn't matter whether the text box was from a Google website or another website. The idea is that Bing was trying to learn from users behavior, and perhaps learn a way it could save users steps in the future.