• by Wendy Davis  @wendyndavis, February 22, 2006

Search marketing costs surged during the fourth quarter, thanks to a combination of increasing cost-per-click prices and a growth in overall number of clicks, according to data released Tuesday by DoubleClick's Performics unit.

Overall, the "cost-per-keyword" rose to around $55 in December, from around $26 at the end of August, according to the report. To arrive at a cost-per-keyword, Performics combines cost-per-click with the volume of clicks; the figure represents the average cost to a marketer of purchasing a keyword for the entire month. The agency declined to release information about average cost-per-click.

DoubleClick attributed the December spike to holiday shopping, which spurred consumers to click on more keywords. Indeed, click volume increased by 48 percent quarter-over-quarter, and more than doubled year-over-year, increasing by around 107 percent from the fourth quarter of 2004.

Marketers also went on a holiday spending spree, upping the number of keywords under management. Active keywords--meaning keywords that triggered a sponsored search link resulting in at least one click--increased by 58 percent from the fourth quarter of 2004.

In January, keyword pricing fell to pre-December levels, as happened last year, said Chris Henger, vice president of marketing and product development for Performics. "The slope in the trend line went right back down, similar to how it performed in years past," Henger said.