von Emarketer:
NEW YORK, NY — (MARKET WIRE) — November 01, 2006 — Just four months ago, marketers were sitting on the sidelines of social networks and watching the traffic surge. Now, advertising on social networks has become a top priority. In 2007, ad spending on US social networking sites is expected to spike to $865 million from $350 million in 2006, according to eMarketer's new report, Social Network Marketing: Ad Spending Update. By 2010, eMarketer estimates, spending will hit $2.15 billion.
via Mashable!