Investment bank Cowen has lowered its projections for U.S. online ad growth, but is maintaining its prediction that the search market will grow 22 percent over last year.

Cowen's new estimate has the online ad market growing 16 percent year-over-year, as opposed to the previously predicted 19 percent.

The new estimate is the latest in a long line of adjusted predictions for 2008. Earlier this year, eMarketer scaled back its estimate for ad growth on social networking sites to $1.4 billion, down from an initial estimate of $1.6 billion.

While display is lagging, search appears to be going strong, despite Yahoo's poor second quarter. Cowen is standing by its search prediction thanks in large part to strong faith in Google, which just experienced a 39 percent jump in revenue.