Despite the continuing slowdown in the expansion of the online advertising economy, its share of advertising budgets will expand significantly during 2009 as most other major media remain flat or decline. Both agencies predict total worldwide ad spending will decline 0.2% during 2009.

As a result, GroupM projects online's share of total ad spending will rise to 13%, while ZenithOptimedia forecasts it will climb to 12.1% from 10.3% in 2008.

"Advertisers are scrutinizing every penny," stated GroupM Futures Director Adam Smith. "The automotive and financial services categories have obviously seen weakness across 2008, and retail will be under pressure as we move beyond its busiest fourth-quarter into 2009. Among our own client base we are not seeing wholesale cancellations, but we are seeing migration from expensive and less-tried-and-true media to value and certainty."

Smith identified Internet ad spending as the only significant growth area, but noted that despite a projected 5% increase in 2009, spending is still down compared to an expected 16% growth this year. He added that the world's other leading Internet economy, the U.K., mirrored U.S. projections with rates of 4% in 2009 compared to 22% in 2008.

"Internet advertising continues to grow rapidly as advertisers turn to it for its innovation and accountability, which is particularly important in a recession when every line of a budget must be justified," ZenithOptimedia wrote in its report, the findings of which will be presented this morning at a UBS media conference in New York by CEO Steven King, along with presentations by GroupM's Smith, and Interpublic's Bob Coen. "We still expect internet advertising to grow by 18% in 2009, including 18% growth in North America and 12% in Western Europe. We forecast the internet to take a 15.6% share of global ad expenditure in 2011, 5.2 percentage points ahead of magazines and 5.6 points behind newspapers, having narrowed the gap from 15.1 points in 2008.

The fact that online ad spending will continue to thrive during the recession of 2009 is noteworthy, because some attribute the recession of 2001 - at least in part - to the Internet, especially to crash of the dot.com economy.