Reaching almost 70% of the Internet's 772 million users (age 15 or older), Google attracted 536 million visitors worldwide in May, an increase of 1.7% from April, according to Internet metrics company comScore.
Microsoft and Yahoo, the number two and three Web properties in the world, drew 528 million and 470 million visitors respectively.
Serial visitation appears to be the habit at these sites, all of which offer search engines: Google visitors popped by 27 times in May on average. Microsoft and Yahoo visitors returned an average of 23 and 22 times that month.
Other sites in the Top Ten received far fewer visits per visitor. Time Warner Network and Fox Media Interactive (MySpace) averaged 12 and 14 visits per visitor. The Time Warner Network was the only Web property in the Top Ten list to show a decline in visitors (-0.1%).
Apple, the 10th ranked Web property worldwide, saw 121 million unique visitors in May, an increase of 5% from the 115 million recorded in April. "This increase precedes the recent U.S. release of the Apple iPhone," said comScore.
eBay and Wikipedia, ranked 5th and 6th in terms of traffic, came in 2nd and 3rd in terms of growth: eBay's visitor count grew by 4.3% in May and Wikipedia's visitor count grew by 4.1% that month.
Looking beyond just the Top Ten Web properties, sites gaining the most traffic in May were Ciao sites (31%), Facebook (21.8%), and Mozilla (18.5%).