Advertising revenues help to keep many net businesses going
The global economic slump has hit net advertising hard in early 2009.
Ad revenues dropped 5% in the first quarter of 2009, according to figures from the Interactive Advertising Bureau (IAB) and analyst firm PwC.
Net ad spend in the US was $5.5bn (£3.46bn) by the end of March, down from $5.8bn in the same period in 2008.
The IAB said the fall was the first significant slump in ad revenues after more than six years of almost uninterrupted increases.
While ad revenues have dropped in a few quarters since 2002, in particular they dipped during mid-2008, the 5% fall is by far the largest ever seen.
"Interactive advertising has taken its rightful place as a fixture on marketing plans across sectors, which means we aren't immune to broader economic trends," said Randall Rothenberg, president of the IAB in a statement.
Despite the fall, analysts said net advertising spending had suffered far less than other sectors during the global slump.
"Current economic conditions are clearly challenging," said David Silverman, a partner at PricewaterhouseCoopers. "Nonetheless, interactive media continues to consume a larger piece of the overall advertising pie."
Mr Rothenberg said he was confident that net advertising would continue to prove popular and bounce back as economic conditions improve.