Despite the company's aggressive spending on a TV ad blitz, the latest figures suggest that Microsoft's Bing search engine has only scored marginal gains in market share. Sometimes, you just can't buy market share. Judging by the latest analysis from Net Applications, that seems to be the lesson Microsoft is learning with its search engine. Bing, debuted just over a year ago, has only marginally improved Microsoft's share of the search market over its previous iteration.