The cash cow constellation

With most teens and nearly 40 percent of adults visiting social-networking sites, advertisers are avidly experimenting on Facebook, MySpace and niche online social networks, according to a new eMarketer report, writes MarketingCharts.

In 2008, US advertisers are expected to spend nearly $1.6 billion — up 69 percent from the $920 million they will have spent in 2007, according to the report, Social Network Marketing: Ad Spending and Usage.

In four years, US ad spend on social-networking sites is expected to reach $2.7 billion:

Social networking may get more than its fair share of media attention, but it is not a fad, said Debra Aho Williamson, author of the report.

The Population of Social Networkers

"In 2007, 37 percent of the US adult internet population and 70 percent of teens used online social networking at least once a month," Williamson said.

That's about 56.9 million adults [age 18+] and 13.6 million teens [age 12-17].

eMarketer predicts that in 2011 the total US adult social-networking audience will grow to more than 85 million, or 49 percent of the US adult internet population.

The greatest growth until then is expected to come in 2008, when 12 million more US adults will become social-network users - for a total of 69.0 million users (43.5 percent of the US adult internet population), according to the forecast.

In addition, by 2011 some 84 percent of online teens in the US - some 17.7 million of them - will also be using social networking on at least a monthly basis, eMarketer forecasts.

Again, the greatest growth in that period is expected to be in 2008, with 1.7 million additional teens - a total of 15.3 million, or 77 percent of US online teens - using social networking.

Ad Revenues Worldwide

Worldwide ad spending on online social networks will increase from more than $1.2 billion in 2007 to more than $2.1 billion in 2008 - or a growth of 75 percent - eMarketer projects.

Globally, social-network ad spending is expected to surpass $4 billion in 2011, including $1.6 billion in spending in the US.

Social-network advertising revenues worldwide are expected to grow to nearly $2.9 billion in 2009 and nearly $3.6 billion in 2010.