The global online audience ages 15 and older accessing the Internet from home and work computers reached one billion in December 2008, according to the data from the comScore World Metrix audience measurement service released Friday.

Forty-one percent of global online users came from the Asia-Pacific region, while 28 percent came from Europe, and 18 percent from North America. Users from Latin America and the Middle East & Africa accounted for niche, with 7 percent and 5 percent, respectively.

"Surpassing one billion global users is a significant landmark in the history of the Internet," said Magid Abraham, president and chief executive officer of comScore. "It is a monument to the increasingly unified global community in which we live and reminds us that the world truly is becoming more flat. The second billion will be online before we know it, and the third billion will arrive even faster than that, until we have a truly global network of interconnected people and ideas that transcend borders and cultural boundaries."

China topped other countries with the biggest online audience base in the world in December 2008, with 180 million users, or 18 percent of total global Web users. The United States came next with 16.2 percent share, followed by Japan (6 percent), Germany (3.7 percent) and the U.K. (3.6 percent), according to comScore.

Google sites were the most popular in Dec., 2008, with 777.9 million visitors. Microsoft sites came in second (647.9 million visitors), while Yahoo! sites (562.6 million visitors) followed. Facebook.com boosted 127-percent in 2008 to 222 million visitors, making it the leading social networking site and the seventh most popular property worldwide.