WebProNews

In 2007, 37 percent of the U.S. adult Internet population used online social networking at least once a month. That number will increase to 49 percent in 2011.

"The continued growth of social networking seems assured," says Debra Aho Williamson, eMarketer Senior Analyst and author of the new report, Social Network Marketing: Ad Spending and Usage, "unless teens stop social networking as they become adults."

In 2006, 61 percent of all U.S. teens visited social a networking site on a monthly basis that number will increase to 70 percent this year. By 2011, one-half of all online adults and 84% of online teens in the US will use social networking each month," says Ms. Williamson. "There is little to suggest that this activity will go away."

When it comes to advertising revenues, eMarketer estimates that global online social network ad spending will grow from $1.2 billion in 2007 to $2.2 billion in 2008. Worldwide spending will hit $4 billion in 2011.

In the U.S., spending is projected to rise to $1.6 million in 2008, from $920 million in 2007. "MySpace and Facebook together receive more than 70% of all US social network ad spending," says Ms. Williamson. "And they are hard at work to convince marketers to allot more of their budgets to social network advertising."

"But if social network marketing delivers on its promise of peer recommendations the flow of advertising dollars will turn into a flood," says Ms. Williamson.