• June 20, 2008

Google maintained its position atop the Web ratings in May, edging out Yahoo by a mere 400,000 unique visitors for an audience of 143.4 million. Microsoft took third again with 121.3 million.

Excluding AOL, Time Warner moved up a notch to the ninth slot with 56 million visitors, while IRS.gov jumped 14 places to rank No. 20 with 31 million. The increase was driven by people checking the status of their tax refunds and stimulus checks.

Other top-gaining sites in May included Proflowers.com, up 319%; Vonage Holdings Corp. (119%); Vlaze Media Networks (78%); and Discovery.com (76%).

Among ad networks, Platform A continued to lead the way, reaching 90% of the U.S. Internet population of 191 million. The Yahoo Network had 86%, Google Ad Network, 83%, and Specific Media, 79%.

--Mark Walsh