A couple days ago, the headlines blared that Bing now has 30 percent search market share in the U.S. Not so fast. Those numbers were based on Hitwise estimates . Today, comScore came out with its own qsearch estimates, which is what Wall Street analysts following Google report. The comScore numbers tell a slightly different story. If you include all searches, then the combined market share of Bing (13.3 percent) and Yahoo (17.7 percent), which is powered by Bing, is indeed 31 percent. But this "core" search number includes Google slideshows, contextual search in places like Yahoo News, and Google Instant. Every time you go through a slideshow on Yahoo, for instance, related search results appear below, inflating its numbers. But ComScore strips out those numbers to come up with what it calls "explicit search" (you know, when someone actually types a query into a search box). When you look at explicit search, Bing and Yahoo combined only had 29.5 percent market share in the first quarter of 2011.