Despite this rapid growth rate, online video still is a relatively small share of total ad spending, and accounts for less than 1% of the total TV advertising marketplace, Wieser said.

Social media ad spending will top $1 billion next year, rising 48.9% over 2007, Wieser predicted.

For all their growth, Wieser said, many of the fastest-growing of the emerging platforms still haven't figured out how to "monetize" their reach in terms of advertising revenues.

For example, he estimated online social networks would take in only about $685 million in advertising revenues this year. That's up a whopping 148% from the $276 million advertisers spent on social networks in 2006, but it's still only a fraction of their relative growth in terms of share of total Internet page views.

Wieser estimated that the page views of social networks would rise nearly 99% this year versus only 2.6% for total Internet page views. These and other emerging platforms--such as mobile marketing, video games, advanced television, and digital out-of-home networks--will actually grow at double the official online advertising growth rate, rising 31.7% in 2007, Wieser forecast.

Universal McCann director of forecasting Bob Coen, who tracks traditional advertising spending, predicted that Internet spending will rise 15% to $10.715 billion in 2007. (That estimate does not include search, social networks or online video.)

Coen issued a downward revision of his 2007 forecast, and said U.S. ad spending is projected to grow only 3.1% in 2007. His earlier forecast, projected in December, had been 4.8%.

Magna Global is a sister agency to Universal.

The side-by-side forecast presentations this week were a symbolic counterpoint, with Coen representing the old world of the advertising economy and Wieser the new one--which some believe may be responsible for sucking some of the wind out of traditional advertising spending.

Asked what the real growth rate would be for the overall advertising economy if the emerging platforms were factored into the total equation, Coen said it could add as much as a half a percentage point to the industry's growth. "Instead of that figure being 3.1%, it might be 3.5% or 3.6%," he said.

But the changes taking place in advertising spending aren't simply a shift from old media to new, said Magna's Wieser, but an even more fundamental redeployment.

"What's actually happening, I would argue, is advertisers are shifting their money out of media that we define as ad-supported media into marketing," said Wieser, adding: "And it's very difficult to measure that."

Some of that spending is going into so-called "below-the-line" marketing services like direct response and promotion that are not classified as advertising budgets, while others are going into new media platforms that have yet to be classified.

Despite its rapid growth, online video, for example, is not expected to have a pronounced impact on conventional TV platforms for at least the foreseeable future, Wieser said. Citing the universal appeal of traditional TV programming and distribution models, he said, "We see that TV actually comes out in pretty good shape. So consequently, we don't expect to see TV taken away quite yet."

In fact, Wieser offered a five-year projection on the popularity of the two video platforms and said that by 2011, Magna believes conventional TV's "popularity" would still be 90 times that of online videos, despite the latter medium's rapid growth rates.

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