Bing Passes Yahoo in Search: Nielsen

Microsoft Bing busted Yahoo's bubble in August, pulling ahead of its search-providing partner 13.9 percent to 13.1 percent. Combined, the companies sport 27 percent market share, Nielsen said. Google holds 65 percent.

The combination of Microsoft's MSN, Windows Live and Bing search properties helped Microsoft overtake Yahoo in search for the first time ever in August, according to researcher Nielsen.

Microsoft's properties tallied 13.9 percent of search volume last month, compared with 13.1 percent for Yahoo, which fell from 14.3 percent share in July. Nielsen provided this line graph of the search figures.

Why the decline? Yahoo is letting Bing power its search results under a 10-year search deal that commenced August 24 in the U.S. That means Yahoo lost a whole week of searches to Bing.

Combined, Microsoft and Yahoo hold a 27 percent share of the search market versus Google, which retained its dominant share of the U.S. search market with 65 percent, Nielsen said.

HitWise said last week that Bing and Yahoo combined for nearly 25 percent of U.S. search queries through their first full week of integration.

When Nielsen reflected on the past year in search volume, Google has seen little change in search share, while Yahoo has dipped from 16.0 percent in August 2009 to 13.1 percent today. Conversely, MSN/Windows Live/Bing's share has grown from 10.7 percent in August 2009 to its current13.9 percent.

It could be that a portion of Yahoo users lost confidence in the company after the search deal was announced July 29, 2009, and switched to Bing, which saw its uptick begin in August 2009.

Things aren't going to get easier for Bing or Yahoo. Google kicked up the pressure on both search engines last week, with the launch of Google Instant, its predictive search technology for letting users find information without typing in complete queries.

The market now awaits comScore numbers for the search-engine market.

The company recently reworked its metrics for counting search queries, taking into account explicit core search-excluding contextual clicks on slideshows-and total core search, which counts total numbers.