This isn't a rumor. This isn't even a speculation. This is just the New York Times saying that Bing is killing Microsoft from the inside, and that if Microsoft wanted to sell, they could maybe do worse than Facebook. Agreed!
Here's the thing: it's no secret that Microsoft loses gobs of money on Bing, quarter after quarter and year after year. It's also no secret that Bing will remain a viable property, if for no other reason than it's Google's only serious competition. Also: it's fun to say.