Mashable ran an article that outlined figures for USA-based searches by both Google and Bing and came up with an unlikely conclusion that it may be possible that Bing will overtake Google in 2012, assuming that the trend continues.

They based their article on stats released 2 days ago by HitWise (first graphic below) and compiles HitWise figures for the last 6 months to come up with their own graph (second graphic).

Then "We decided to graph out the answer to that question. In this scenario, Google drops 3% of its market share each month, while Bing gains 5% each month. Of course, this assumes sustained growth and sustained losses on the parts of both search engines. In a volatile market, it is extremely unlikely that we’ll see these exact numbers over the next year." (third graphic).

I don't think the predicted figures are likely, but there is some logic behind them and who knows, it may just happen???? But bottom line here is that Bing is actually growing, which is important for us to remember when doing SEO work!