Bing launched in June 2009 with 8.9 percent of searches, the share of the market that had been going through Microsoft's Live search, and climbed to 12.7 percent by June 2010. But Bing's growth slowed in July, according to comScore.
The new report says Bing's market share actually dipped by .1 percent from June to July 2010, giving it 12.6 percent of the search market.
Google lost 1 percent of the market in the same period but still grabs 61.6 percent of searches. Yahoo! gained 1.2 percent to claim 20.1 percent of searches. Ask.com lost .1 percent, leaving it with 3.5 percent of the market, and AOL was unchanged with 2.2 percent of the market.
But Yahoo! has already started switching over its search backend to be powered by Bing. The transition could give Microsoft control over almost a third of the market, making it a healthy competitor to Google.
The increased exposure brought about by the "powered by Bing" graphic that would appear on Yahoo! sites could also kick more searches Bing's way.
It's also interesting to note that this report is the first to include comScore's new metric, "explicit core searches," designed to measure only searches performed intentionally by users. ComScore was concerned that the practice of linking users directly to search results was inflating market share for some search engines.
Using the new metric, Google claims 65.8 percent of searches, Yahoo! 17.1 percent and Bing 11 percent.
ComScore has been publishing search market share reports since 2003, but there are other reports that contradict its numbers - numbers just released by analytics firm Chitika show Google with a whopping 81 percent of the market, Bing with 11 percent and Yahoo with just six percent.