DoubleClick's Performics has issued the fourth-quarter results of its Performics 50 index related to paid search advertising, and according to its "Search Trend Report Q4 2005" report (pdf), four trends marked the end of the year. First, search campaigns are getting larger, with 4Q05 total number of clicks for campaigns tracked by the index increasing 107 percent from 4Q04, and the average number of active keywords kept under management by marketers increasing 58 percent. Second, cost per Keyword (CPK) and Cost per Click (CPC) rose dramatically during the holiday season.

Average CPK increased from $25.50 in September to $54.62 in December 2005. DoubleClick said the increases were in pat the result of seasonal effects, combined with lower-priced keywords making up a smaller and smaller percentage of campaigns.

Fourth, December accounted for nearly half of all conversions, not surprisingly, since online marketers - and consumers - spend big during the holiday season. Some 40 percent of all clicks and 48 percent of all conversions among the Performics 50 in the fourth quarter occurred in December.

According to Performics, holiday shoppers went further down the page. That is, compared with November, a greater percentage of conversions in December from paid search ads ranked lower than second. Last year, however, that effect was more pronounced.