The U.S economy has been on a roller-coaster ride, and the question was just when and how severely it would affect the media economy.

There are at least some answers. Though 2007 was not a strong year to begin with, the slowdown really kicked in during the fourth quarter, according to a report out this morning from TNS Media Intelligence.

Ad spending stopped growing and actually declined over the three months, sliding 0.1 percent. That left total 2007 spending also about flat, with a gain of just 0.2 percent over 2006.

More significant, the malaise that set in over those months has continued into this year, according to TNS, raising new worries that the ad economy will see yet another flat year, despite heavy spending on elections and the Summer Olympics in China.

It certainly puts into doubt a TNS forecast released in January for a 4.2 percent growth in media spending in 2008.

Indeed, media buyers report an increasing hesitancy on the part of clients to commit to aggressive media plans as they keep one eye on Wall Street and the other on Main Street for further signs of recession and consumers cutting back.

Within the various media tracked by TNS, the internet led in spending growth in 2007, up 15.9 percent for the year, to $11.31 billion (see charts, below).

But also seeing solid growth were consumer magazines, which were up 7 percent, to $24.43 billion, despite weak performances by such important categories as business magazines and newsweeklies.

Total spending on television was actually down for the year, off 1.7 percent, to $64.42 billion, dragged down by spot TV, which was off 10.2 percent for the year, and network TV, which was down 2.0 percent. Cable led TV spending increases, up 6.5 percent.