Google increased its search share to 66.3 percent through October, from 66.1 percent in September, with challenger Microsoft Bing growing from 11.2 percent to 11.5 percent over the same period.
ComScore said the total queries powered by Google's engine on partner sites, such as AOL and Ask, rose a touch, to 69.2 percent, from 69.1 percent for the month.
Susquehanna Research suggested Google's Instant predictive search, which lets users see results as they type their query, "appears to have had a favorable impact on overall core query volumes" in its first full month of operation.
However, several Instant searches may have been excluded from explicit core search.
ComScore counts explicit searches as those in which a user hits "enter," clicks on an algorithmic or sponsored result, clicks one of the refinement links, or executes a query by clicking on a vertical search tab.
If a query occurs without such an explicit action or includes a "pause" of at least three seconds-such as would occur because of a contextual shortcut or slideshow-it it is excluded from explicit core query figures.
"If we assume that all of Google's nonexplicit searches are a result of Instant searches, and are not contextual in nature, Instant queries may have accounted for seven percent of Google's total core search volume and nine percentage points of its total year-over-year core search growth of 26.5 percent" in October, said Susquehanna analyst Marianne Wolk.
Wolk added that the new Instant Previews launched this month may boost query volume over time.
Although it appears distant in Google's rearview mirror, Microsoft has grown Bing search from 8 percent in June 2009 to 11.5 percent last month, the greatest growth spurt of any search provider.
This is no mean feat versus Google, which has been at around a 65 percent share in the U.S. for several years.
Jefferies and Co analyst Youssef Squali said that because certain Bing results will also be integrated with Facebook's "like" and "dislike" buttons, "we expect a pick-up in Microsoft's search results over the next couple of months as these features are deployed."
Bing also officially powers Yahoo's search results and search ad clicks and could very well see an uptick from that. However, Yahoo hauled in 16.5 percent of traffic in its second full month of being powered by Bing, down from 16.7 percent in September.
Nevertheless, said Wolk, Yahoo's search transition to Bing might improve results in November, December and 2011.
This may have been cause for disappointment in the past for Yahoo investors. But Yahoo CEO Carol Bartz made it clear that search was not the company's focus when she worked with Microsoft CEO Steve Ballmer in 2009 to offload the Yahoo search backend to Bing.
Then, at the Web 2.0 Summit Nov. 16, Bartz said that her company is not a search company, but one of "content, communications, media and innovation."
Against that backdrop, there are fresh whispers that private equity firms want former News Corp. President and COO Peter Chernin to assume a leadership role at Yahoo.