Citigroup vs JPMorgan: Ads Up! Ads Down! Up!

Interesting that the same day JPMorgan comes out with a bullish upgrade on its paid search forecast for 2008, my friend Mark Mahaney at Citi has tempered his U.S. ad growth forecast. On what is, I think, an apples-to-apples basis, the former has a new report out looking for a 31.9% increase, while the latter is looking for 22% growth. That’s a material difference, and a 400-basis-point cut, in Mark’s ad growth model, from 2007.

Just for interest, Mark’s top three net picks for 2008 are EXPE, GOOG, and MNST.