Though most prognosticators expects moderate overall ad spending growth in 2007, online advertising budgets are expected surge, according to a leading ad forecaster.

The growth forecast for online advertising is roughly seven times that of major media overall, according to Publicis Groupe's ZenithOptimedia, reports MediaPost. "Internet ad spend will grow 28.2 precent in 2007, while the rest of the market grows 3.9 percent," the media agency said in its most recent quarterly ad spending report. "Apart from the internet, only cinema and outdoor are forecast to grow faster than the market to 2009," it predicted.

Paid search is the largest sector in online advertising and will account for nearly $14 billion in global ad spending in 2007, Zenith said; display advertising, including broadband video, is among the fastest growing and is forecast to account for $10.5 billion in ad spend; online classified ranks third with a forecast of $6.2 billion in 2007, followed by $721 million for other media, such as email and mobile.

"It has taken only 11 years [for internet] to overtake two long-established media: cinema (which it overtook in 1997) and outdoor (which it overtook this year), and by 2009 it will be larger than radio," ZenithOptimedia said.