Google's share of U.S. Web searches rose in April, while Yahoo and Microsoft recorded declines, a Web intelligence firm said Wednesday.

Google's share increased to 67.9% from 67.25% in March, Hitwise said. Year to year, Google's share was up from 65.26%.

No. 2 Yahoo, meanwhile, saw its share dip to 20.28% from 20.29% in March and 20.73% a year ago. Microsoft's share also declined to 6.26% from 6.65% and 7.77%, respectively.

Ask.com, which is fourth in the market, increased its share from 4.17% from 4.09% the previous month and from 3.69% in April 2007. The remaining 45 search engines monitored by Hitwise accounted for a total of 1.4% of U.S. searches.

The market share numbers are important because search engines continue to be the primary way Internet users navigate to key commercial segments. From April 2007 to 2008, travel, entertainment, business and finance, sports, online video, and social networking categories showed double-digit increases in their share of traffic coming directly from search engines, according to Hitwise.

Microsoft attempted to narrow the huge lead Google has in the search market by launching a takeover attempt of Yahoo. Microsoft, however, decided to abandon the buyout this month after the two sides couldn't come to terms on price.

The attempted merger, however, may not be dead. The Reuters news agency on Wednesday reported that billionaire investor Carl Icahn was considering launching a campaign to get new board members at Yahoo. Icahn, who has built a stake in Yahoo over the last week, would attempt to elect board members willing to force the Web portal back to the negotiating table with Microsoft, Reuters said.