A large plurality of media buyers and planners are relying more on ad networks today than two years ago, with 42 percent of those who use them saying they now spend more with those networks than they did in 2003, writes MediaPost, citing the results of a ValueClick Media/FastClick study. Some 30 percent of respondents reported spending unchanged from two years ago, 16 percent said ad network spending had declined, 12 percent said they did not know.

The most common reason (46 percent) for not working with an ad network was respondents' concern about where ads would appear, and 38 percent also said they worried about the quality of sites. The most common reasons cited for using networks were reach (72 percent of respondents) and targeting (56 percent).

ValueClick and Fastclick merged in September. The study was based on an August survey of 300 media executives conducted online by Insight Express using members of the MediaPost advisory panel.