Microsoft has been plugging away with its Bing search engine, and according to a recent report it may have finally overtaken Yahoo for the number two spot in US search marketshare. According to comScore, Bing accounted for 15.1 percent of searches in December; Yahoo brought in just 14 percent. It's a big milestone for Microsoft on the surface, but this particular shift has more to do with Yahoo's decline at the hands of Google than it does with Bing. Yahoo's share of searches dropped 0.6 percent from November to December, while Google saw a 0.5 percent increase, giving it a commanding 65.9 percent marketshare. In comparison, Bing saw just a 0.1 percent increase.

That's not to say that Microsoft's service hasn't hasn't made strides. In December of 2010 it accounted for only 12 percent of US searches — and Google's overall share has dropped from the 66.6 percent it held at the same time. While there is a larger trend here, the movements are still relatively minor, and Bing has a very long way to go.