This will be a tough but not disastrous year for TV advertising, with the Olympics and the elections more or less propping up revenues. A new study by Screen Digest forecasts a sluggish 1.5 percent increase in ad spending. (Marketing Charts has the highlights.) But next year there won't be any props, and that could present a dicey market. “Advertising spending tends to amplify economic cycles - and in some instances it actually anticipates downturns. Although we’re not expecting advertising budgets to be affected this year, thanks to the quadrennial events…we’ll experience the real impact in 2009,” said Vincent Létang, Screen Digest senior analyst. The most intriguing part of the report is the long-range forecast (always fun because you can be outrageous in your guesses, er, predictions, and who will remember to call you on them?). By 2012, Screen Digest predicts, advertising will be a three-tier market, with online at the top, TV in the middle and other traditional media – presumably newspapers and magazines - bringing up the rear.