engine - 3:33 pm on May 23, 2008 (gmt 0)
In April, Google Sites extended its share of core searches to 61.6 percent, up from 59.8 percent the previous month. Yahoo! Sites ranked second with 20.4 percent, followed by Microsoft Sites (9.1 percent), AOL LLC (4.6 percent), and Ask Network (4.3 percent).
ComScore April 2008 U.S. Search Ranking [comscore.com]