Bing caught copying search results from Google
Google first suspected foul play in May 2010. By October 2010, with Bing results beginning to look uncannily like Google's, it knew something had to be done about it -- and so, in true, nerdtastic style, Google set up a sting to prove that Microsoft was actually behind the wholesale mimicry of Google's search results.
Google injected "synthetic" results into its search engine -- fake queries and results that no real user or engine would ever generate. Then, on D-Day, December 17, about 20 Google engineers were asked to run the test queries with Internet Explorer 8, Bing Bar and Suggested Sites. By December 31, some of these fake results began appearing on Bing. See the examples after the break -- it's damning.
For a full discussion of Bing's antics, and what repercussions Microsoft might have to face, read the original Search Engine Land post.
One of Google's 'sting' queries
A few days later, the same result on Bing
[Images unceremoniously borrowed from Search Engine Land]