Summary.... Screen Digest has revised its forecasts for online advertising in the US downwards following a weak fourth quarter 2008 for the medium. Screen Digest now expects online advertising to decline 4.8% in 2009 to $22.8bn. This follows six years of successive double-digit growth. We expect all sub-categories except online video to decline in 2009. We expect display to decline 3.6%, with a 26% rise in video ads offsetting an 8.8% slump in other forms of display. Other forms of online advertising (search and classified) will decline 5.5%.