Amit Singhal, a Google Fellow, went ballistic in a blog post on the company's website about how Bing was passing Google Search results as its own.
Singhal explained how Google used a number of "honeypot" terms (otherwise known as synthetic queries) to lure Microsoft together with 20 laptops with Windows OS, Internet Explorer 8 and Bing Toolbar.
The fact that Microsoft used Google's results is not surprising in itself; it is likely that Internet Explorer and Bing Toolbar send data to Microsoft via its customer experience improvement program, something that all users can opt out from voluntarily.
One commentator pointed out that Bing's method of using inputs from millions of users is actually a very clever one since it allows the search engine to discover content that was previously invisible.
This, according to Harry Shum, Bing Corporate Vice President, is one of the most 1,000 different signals used by Bing in its search algorithm.
Whether what Microsoft did was reprehensible is very subjective; search engine expert Danny Sullivan of Searchengineland, says that he tends "to feel like it's something Bing shouldn't do" but then doesn't Google collect usage statistics via Google Toolbar on its Internet Explorer?
Maybe someone should track down whether Google uses statistics from Bing click throughs to help its search results; that would be an interesting exercise.