Search Party Losing Steam

A change in ad spending threatens to cool the pace of search-engine growth.

For years, Google (GOOG Quote) and its many search rivals have benefited from the shift of traditional advertising to the Web. But now, some money may be moving away from search, which has been the hottest category, and toward other Web vehicles, amid questions about paid search ads' effectiveness.

Last year, search accounted for about 31% of the gross billings of aQuantive's (AQNT Quote) Avenue A/Razorfish business. But that share will likely drop 2 or 3 percentage points this year as advertisers boost the money they spend on advertising through portals including Yahoo!(YHOO Quote) and niche Web sites. ...