A leading Web analytics firm reported Thursday that soon-to-be partners Bing and Yahoo each gained a little share of the marker from search leader Google in June.

Search engine mavens at comScore (NASDAQ: SCOR) found that Microsoft (NASDAQ: MSFT) Bing and Yahoo (NASDAQ: YHOO) each inched up 0.6 percentage points in June. Bing, the third-place search engine, now slightly more than 13 months old, was up from 12.1 percent of U.S. searches in May to 12.7 percent in June.

At the same time, perennial second-place search engine Yahoo saw its usage grew from 18.3 percent search share in May to 18.9 percent in June, according to comScore.

Meanwhile, Google (NASDAQ: GOOG) slipped slightly from a 63.7 percent search share in May to 62.6 percent of U.S. searches in June -- a decline of 1.1 percentage points. Overall, U.S. searches hit 16.4 billion for June, a gain of 3 percent over May's search totals. Those tallies represent 10.3 billion searches for Google, 3.1 billion for Yahoo and 2.1 billion for Bing.

However, search engine optimization (SEO) consultants and search advertising buyers may want to take the latest numbers with a grain of salt, because the tracking firm has not yet resolved issues related to Bing and Yahoo recently implementing "slide show" features that can be counted as searches when users roll their cursors over them.

ComScore has said that it is working on ways to resolve the problems in how searches are tallied, but has not yet those changes in effect. "Both Yahoo sites and Microsoft sites have experienced gains due in part to the continued utilization of contextual search approaches that tie content and related search results together," comScore said in a statement.

However, in a blog post in June, Cameron Meierhoefer, comScore's executive vice president of analytics, said the company will implement the changes "ideally starting with the release of July data in the first half of August."

Microsoft launched Bing at the very end of May 2009. Since that time, it has slowly eked out mild growth against Google.

In the meantime, the deal that Yahoo and Microsoft made last year in which Yahoo will begin using Bing as its underlying search infrastructure in return for Microsoft receiving a small cut of the advertising revenues, has yet to take effect. However, if that technology merger were to take place this month, it would give Bing a total of 31.6 percent share of U.S. searches, just under half of Google's 62.6 percent.

Stuart J. Johnston is a contributing writer at InternetNews.com, the news service of Internet.com, the network for technology professionals. Follow him on Twitter @stuartj1000.

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