Jupiter Media Metrix has reported that contrary to widespread belief, advertising buys across fewer online networks are often far less efficient than buys across several networks.

The company did a quantitative study of three popular categories of ad-supported Internet sites - news, finance and music. It found that placing a four-week ad campaign of four million impressions on any one of the leading four sites would reach an audience of 1.4 to 1.9 million unique visitors. However, spreading those four million impressions across three of the top four sites within each category substantially broadens the audience reach from 2.2 to 2.5 million unique visitors.

Moreover, the audience reach can be increased by up to an additional seven per cent by spreading the same four million ad impressions to four sites.

Target audiences are often fragmented across multiple sites, thereby limiting the ability of one or just a few sites to efficiently reach a greater number of defined audience members. Conversely, advertisers looking to increase frequency in a campaign may very well lean toward advertising on fewer sites.

For this analysis, four leading sites and portal channels were selected in each of the three categories:
News

Average Audience Reached with a Four-Million Impression Ad Campaign August 2001 - At home/work combined in the U.S.

Unique Visitors Reached for Each Category of Site (in millions)