A report by StatCounter suggests that Microsoft's new search engine, Bing, has overtaken Yahoo’s U.S. market share a few days after its June 1 rollout.

The online traffic-analysis firm found that, on June 4, Bing had a 16.28 percent market share, ahead of Yahoo at 10.22 percent, but lagging far behind Google at 71.47 percent.

However, the spike may be a temporary one, fueled by the massive amounts of advertising monies devoted by Microsoft to the project. According to a June 5 report in The New York Times, Microsoft plans on spending between $80 million and $100 million on the effort, even integrating paid content into online video sites such as Hulu.com.

"It remains to be seen if Bing falls away after the initial novelty and promotion," Aodhan Cullen, CEO of StatCounter, said in a statement.

On its site, StatCounter says that it "currently has over two million members and tracks in excess of ten billion pageloads per month over its network of three million websites."

Others in the IT industry have remained skeptical about Bing's chances, including Yahoo CEO Carol Bartz, who suggested during the Bank of America and Merrill Lynch U.S. Technology Conference on May 3 that interest in Bing would be "temporary."

"They’re not going to get scale through Bing," she added, referring to Microsoft.

Microsoft launched Bing a full two days earlier than expected, on June 1. The search engine operates in a traditional manner, providing a page of hyperlinks in response to a query, but also features tabs that users can click on for a more granular search. Tab categories include "Images," "Videos," "Shopping," "News," "Maps," and "Travel."

Although a ComScore report had Google claiming 64.2 percent of the U.S. core search-engine market in April 2009, Microsoft seems determined to carve out its own territory within the space. That same report had its search-engine market share in third, with 8.2 percent, behind Yahoo with 20.4 percent.