Microsoft's share of the search engine market dropped in May, before the release of Bing, according to a June 16 report issued by research firm Nielsen.
The report suggested that the number of people conducting online searches via Microsoft's sites dropped by 14.6 percent year-over-year. By contrast, year-over-year growth for Yahoo and Google reached 22.3 and 28.2 percent, respectively.
The overall search market grew 20.3 percent during the same period, from 7.8 billion searches in May 2008 to 9.4 billion in May 2009.
However, Nielsen suggests that Microsoft outperformed Google in at least one metric, with users spending 2 hours, 23 minutes on Microsoft-related sites or using Microsoft's Web-based applications, versus 1 hour, 52 minutes for Google. Yahoo came in first in that particular ranking, with users spending 3 hours, 13 minutes with its sites or applications.
The number of people conducting online searches with Microsoft could switch with the rollout of Bing. In addition to offering traditional search, with pages of hyperlinks in response to a query, the search engine also offers users specific categories, such as "Shopping" and "Videos," for a more granular search.
By some reports, Bing exhibited a solid post-launch performance; a ComScore survey released June 9 suggested that Microsoft's rate of searcher penetration for its sites had gained 1.7 percent following the search engine's June 1 debut, to 15.5 percent. During that same period, Microsoft's share of search-results pages increased by 2 percent, to 11.1 percent market share.
The ComScore report suggested that the increased rate of searcher penetration, which represents the average daily penetration among U.S. searchers, is "an indication that the search engine is reaching more people than before."
However, wrote Mike Hurt, senior vice president of ComScore, "The ultimate performance of Bing depends on the extent to which it generates more trial through its extensive launch campaign and whether it retains those trial users."
Within the first few days of Bing's launch, an early report from StatCounter had the search engine overtaking Yahoo in U.S. market share, with 16.28 percent of the market versus Yahoo's 10.22 percent. However, these figures were later disputed by Nielsen and other Web traffic-tracking firms, which suggested that Yahoo's position was safe for the moment.
Microsoft's major push behind Bing apparently includes an advertising budget of between $80 million and $100 million, according to The New York Times; the company has been promoting the search engine through a number of channels, including paid content on Hulu.com.