From search engine land ... Google: Bing Is Cheating, Copying Our Search Results
"Google has run a sting operation that it says proves Bing has been watching what people search for on Google, the sites they select from Google's results, then uses that information to improve Bing's own search listings. Bing doesn't deny this."
Corporate cheating like this is common. I have heard that McDonald's spent a lot of time determining where to open up a restaurant, while Burger King just found a property near McDonald's. This is a leader/follower game. In this case however, Google made some intentionally absurd search queries and results to trap Bing, and Bing fell for the trap, as if McDonald's had built in Potemkin Village, and Burger King followed.
Transportation has had similar copy-cat experiences, consider the number of trans-continental railroads in the United States built in the 19th century. Or copy-cat car designs. In this case the copying occurred without any human check on the output, which is what makes it more interesting.
I have had students plagiarize before, some so badly they left the copyright symbol on their cut-and-paste masterpiece. I guess Microsoft was too lazy to do the real work of designing in a search engine that produced good results, so they just copied someone else's.