Nielsen/NetRatings reports that Google accounted for 50 percent of all US searches conducted in April, followed by Yahoo! and MSN, with 22 and 11 percent.
However, Google is not the leading web site of the US, nor does it control the social networking scene.
According to NetRatings Yahoo! had the most popular set of web sites ( including Yahoo mail) in April, with a unique audience of 105 million. Microsoft.com was number 2, msn.com — another Microsoft property — number 3 and Google.com number 4 (with an audience of 92 million).
Source: Pandia Search Engine News