I've done a bit of egosurfing today (http://en.wikipedia.org/wiki/Egosurfing) and found that my code review system (http:/malevich.codeplex.com) shows up as #2 when searching for Malevich in Bing.
Frankly, I was surprised.
By comparison, Google search has it towards the bottom of the second page. Mondrian - Google's own code review tool which inspired Malevich - is at the very bottom of the first page.
Now, there was a fresh batch of conspiracy theories fomented by the "technical" pundits that claim that Microsoft uses Bing put down Apple (http://www.pcworld.com/article/169750/bing_search_reveals_promicrosoft_results.html). To me this is like a toddler pushing a nuclear submarine to help it go faster: Windows certainly does not need help from Bing to compete with Apple.
I think there is a very simple explanation for both Malevich and Mac vs PC phenomena. The search engine certainly uses clickthrough data to guide its searches. Bing's biggest market share in the geek population is Microsoft employees - there are tens of thousands people here that use Bing. The overall market share of Bing is small enough so that a few thousand users can swing the search results considerably - bringing Malevich-the-code-review-system (which is also extremely popular here) and articles critical of Apple on top.
Admittedly, this is not nearly as juicy as the "evil Microsoft adjust the search results to favor itself" conspiracy theories, but it appears to be the simplest one :-).