Bing stands for "But It's Not Google". As in: "I would use it, ..."
They're doing this because customers really
don't care for Microsoft:
During regular “blind taste tests,” in which Microsoft asks randomly-selected consumers to score the quality of results from various Internet search engines, the quality of Microsoft’s search results have so improved that people can’t tell the difference between Microsoft and Google search results, says Mr. Mehdi, senior vice president of Microsoft’s online audience business group. But when Microsoft slaps the Google brand name on the results from Microsoft’s own search engine during another portion of its tests, users invariably score them highest.
There's also a lot of searches that Microsoft
probably hates to see:
Microsoft's Live Search revamp apparently cannot come soon enough. Hitwise data shows that the most commonly searched term on Live Search over the last four weeks has been 'Google', accounting for 1% of all queries. Number two? 'Yahoo'.
So you probably won't see the word "Microsoft" unless you dig way into Bing. They're blowing $100 million on ads that I'd also bet don't say "Microsoft". I can already imagine an ad for something called "Bing": a series of superficially diverse people saying, "Gee, I wish I had X" and then they play a bing noise and cut to the same shot with the item in their hand and smiling. Build up to a "wacky" situation or repeat a few times, then overlay a logo.