A record high population of 1.2 billion Internet users ages 15 or older spent a total of nearly 27 billion hours online in September, according to the study.

"The Internet continues to be a dynamic and growing environment around the world with the global online population climbing more than 20 percent in the last year," said comScore Media Metrix executive vice president Jack Flanagan.

Microsoft websites accounted for 14.5 percent of minutes spent online worldwide in September, making it "the most engaging global property," comScore reported.

Google websites was ranked second overall, accounting for 9.3 percent of people's Internet time, followed by Yahoo! and Facebook with 6.3 and 5.1 percent respectively.

Online video-sharing star YouTube accounted for almost half of the 2.5 billion hours people spent at Google websites, according to the study.

Nearly 70 percent of the time spent at Microsoft websites was at the US software giant's Windows Live Messenger service, comScore reported.

Hours spent at leading social networking service Facebook nearly tripled from the same month a year earlier.

Website popularity varied by region, with Microsoft properties finishing in top spots in Europe, Latin America, Africa and the Middle East.

Yahoo! commanded the largest share of online time in North America and attracted a "notable" 7.9-percent share of the hours spent on the Internet that month in the Asia Pacific region, according to comScore.

Websites owned by China-based Tencent Inc. were the most popular properties in the Asia Pacific region, accounting for 10.7 percent of the time spent online there but almost none anywhere else, the tracking agency reported.

Tencent's online offerings include games, social networks, auctions, and an instant messaging service.

(c) 2009 AFP