Although Yahoo still leads Bing in most measures of search market share, Microsoft's search engine has passed up Yahoo, according to one tracking firm.
Nielsen, which says its numbers reflect only queries typed into a search box, has Bing at 13.9 percent, just ahead of Yahoo's 13.1 percent. Google is still the dominant market leader with roughly 65 percent of the market.
In the past year, Yahoo has seen its share slip 2.9 percentage points, while Microsoft's search engine has gained 3.2 percentage points. Google is little changed from a year earlier. And of course, with a search deal going into effect last month, Bing is now powering Yahoo's search results in the U.S.
"Nielsen's search data only counts genuine intentional searches that people type into a search box," the company noted in a statement accompanying the August figures. "It does not include non-intended or 'contextual' searches that are automatically generated by search engines based on a person's browsing behavior."
Although Microsoft has passed Yahoo by Nielsen's method, Yahoo still had a significant lead in July, according to the more widely cited Comscore numbers, including a core search measure that excludes some of the slideshows and other non-explicit searches that had been giving some providers--especially Yahoo--a boost.
Here's a chart of the Nielsen numbers and the recent trend among the leading search providers.