• by Shankar Gupta , February 2, 2007

Media research firm comScore Networks has begun offering data on the reach and frequency of 20 major ad networks, allowing media planners to compare their reach with those of individual Web properties, side-by-side.

Jeff Hackett, comScore's director of agency relations, said the tool was intended to help agencies plan ad buys across a variety of sites and networks. "When planners are using our Media Metrix system, they can pull categories, but now they can to go into our Reach Metrix to really include ad network placements in addition to Web sites," he said.

Hackett said that the ad networks now tracked by comScore have significant reach compared to stand-alone properties. "Ad networks have really massive reach. We're seeing at least 15 of our reported ad networks reach over a quarter of everyone online," he said. "Overall, the ad networks can line up really well with a Web vehicle, if not exceed their reach."

Some of the networks reported by comScore do not disclose their media partners, and comScore keeps those lists of sites confidential, while reporting the total reach of each network. Networks included in the tallies include the five largest: Advertising.com, ValueClick, Tribal Fusion, Casale Media Network, and BlueLithium. Also included are Burst Media, Vibrant Media, Undertone Networks, AdBrite and others.