The bad news for ad sales: it's going to get worse before it gets better.

Barclays analyst Douglas Anmuth submitted the latest discouraging sign today with a revised forecast that anticipates ad revenue declining 10 percent next year, and rebounding slightly with a 1 percent increase in 2010.

Anmuth's latest is a darker picture than his October analysis, which had 2009 ad revenue dropping 5.5 percent.

In the online sector, Anmuth looks for 2009 revenue of $25.1 billion, accounting for 10 percent of overall spending. By that guideline, Internet ad revenue would post a 6 percent gain from the estimate for 2008, driven by a 4 percent increase in display spending and a 20 percent increase in search.

And who's in the best position to weather the storm? Who else -- Google. Anmuth names Google, Discovery and Omnicom as the three media stocks likely to outperform their peers in what could be a very solemn economic year.

Looking ahead to 2010, Anmuth expects online advertising to bounce back with 12 percent year-to-year growth and revenues totaling $28.1 billion.