Microsoft's Bing search engine captured 13.1 percent market share, grabbing an entire percentage point from Google, which dropped from 66.6 percent through December to 65.6 percent through January.
ComScore said Bing, whose share climbed from 12 percent in December, enjoyed its greatest single-month boost since its inception in June 2009, when the service started at 8 percent.
Meanwhile, Yahoo's search share rose a smidgen to 16.1 percent in January from 16 percent the prior month. Bing powers Yahoo's search, but researchers continue to count Yahoo separately. Together, Yahoo and Bing make up 29.2 percent share, the closest the companies have come to Google combined.
However, Piper Jaffray analyst Gene Munster said he viewed the ComScore stats as bad for both Google and Yahoo, as Bing continues to gain on its new partner, for whom it has been powering search since last August.
"ComScore noted that some of the share taken by Bing is a result of distribution agreements taken over by Bing," Munster wrote in a research note Feb. 11. "However, we believe the gains for Bing demonstrate that Microsoft has no intention of giving up on the search front."
That certainly seems to be the case. Bing Feb. 10 began testing personalized search, which returns results based on previous searches.
For example, when a user searches Bing for the same search term several times and clicks on a link down in the results page, Bing will begin surfacing that link to the top of the page for subsequent searches.
The assumption is that if a user keeps clicking on the same result, it must be important to that user, so Bing wants to surface that information higher up in its results. Bing will also tailor results based on location, specifically targeting results to a user's city.
For example, a Manhattan-based user searching for movie listings in New York City can simply type "movie listings" and Bing will retrieve results to movie show times and cinemas in that city. The idea is to get users to their information faster. Bing offered more information about how this works in a blog post, but those seeking a thorough exam should read Danny Sullivan's post at Search Engine Land.
Google has been offering personalized search for a couple of years (including in its suggested search), orienting results based on the frequency of similar searches and users' locations.
The company is no doubt smirking a tad over Bing's news, privately welcoming its rival to the personalized search party.
Bing's move is particularly salient coming after Google search engineers Feb. 1 accused Bing of copying search results for certain queries.
Bing denied the claims, allowing that its Bing toolbar and Suggested Sites tool simply siphon clickstream data from the collective Web to improve its results.
The debate devolved into a back-and-forth with no resolution. It's interesting to note that both Bing and Google seem to be involved in a copycat tit-for-tat.
With Google as the 12-year-old incumbent, Bing appears to be copying a lot of feature functionality. Google meanwhile appears to be copying some of Bing's user interface and graphical flair.