The indefatigable Ashkan Karbasfrooshan of HipMojo is the first I’ve seen to post on the report on IDC’s data on Q4 online advertising growth.

Online spending grew by 28% to $7.3 billion

This is shocking because Q3 2007 was the first quarter ever where online ad spend in the US surpassed $5B. So for it to grow to $7.3B in Q4 is very bullish.

Numbers like this indicate that even if the likely U.S. recession slows advertiser spending in 2008, it realistically will be TV and print taking the hit. There is no reason to expect that online advertising spends will decrease or even flatten off in that same period. IDC agrees.

Fred Aun of ClickZ Media covered the report is further detail

IDC analyst Karsten Weide said businesses affected by the slowing U.S. economy will slash other advertising budgets before paring their online campaigns. “We think there will be some effect on ad spending overall, but we think online ad spending will almost be unaffected even if there’s a depression,” he said.

IDC also reported that in comparison to the late 90’s

It’s a well accepted means of advertising now and in fact many advertisers say Internet advertising is more effective than other forms.