According to SearchEngineLand, Google’s suspicions were first aroused in May 2010, when it wondered why Bing was getting so good at feeding back the same or similar search results to its own engine. It was even returning the same results for misspelled words, even though Google was correcting the spelling and Bing was not. Further sharp increases in suspicious overlaps in search results in October 2010 raised more alarm bells for Google.
At this stage, however, there was no proof, so Google decided to launch a sting operation to catch Bing in the act. It searched for obscure and little used terms which came back with 0 results for Google or Bing.
Then it manually ranked around 100 synthetic search pages for these terms and checked its own results, which returned pages, while Bing continued to return nothing since it had not been manually altered to do so.
However, after a few weeks of Google employees using Internet Explorer to search for the results in both Google and Bing, Microsoft’s search engine started to magically display the forced search results that Google had orchestrated, heavily suggesting that it was copying Google’s results.
Only about 10 percent of the 100 tests ended with the alleged Bing copying, which baffled Google, but it was enough to indicate that Bing might be up to no good. Google didn’t say it was illegal – since it isn’t losing any money from it – but if it can provide this evidence in a case against Microsoft there could be a dispute on the cards.
At time of publication Microsoft has not denied the accusation.