Study finds knowledge of audience dynamics increases ad reach of Web consumers.

Advertisers must learn how to reach light Internet users and specific target groups and optimize scheduling to take advantage of site usage peaks, according to "Internet Audience Dynamics," a joint research study from DoubleClick Inc. and comScore Media Metrix. The study analyzed the behavior of 1.5 million Web users over a month long period.

"In both television and print advertising, audience accumulation is always a fact in assessing reach, and the same principle can be applied to the Web," says Lynn Bolger, executive vice president, agency development, comScore.

Historically, advertisers analyzed Web audiences in terms of monthly delivery. But, according to the report, total monthly audience data offers little insight into how a site can deliver reach for specific advertisers' schedules. Advertisers need to realize that a Web site's audience ebbs and flows and adjust their ad buys accordingly.

The report found that certain sites' audience patterns are directly affected by their content offerings. Therefore, advertisers should be conscious of their scheduling tactics in relation to audience dynamics. The Wall Street Journal site, WSJ.com, has high usage in the morning and at the end of the workday while Yahoo! Movies sees usage peaks on weekend evenings.

The report found that light Internet users are heavy users on certain sites. Heavy Internet users are defined as those who go online 19 days or more in a month. The report found the best way to reach light users is through smaller sites like CNN.com rather than big portals such as AOL, MSN and Yahoo. Almost half of the pages views on the CNN.com home page (49.3 percent) are viewed by light Web users who make up the 36.2 percent of the home page audience.

Another key finding was that high placement of ads on busy Web sites is not always consistent with high reach. The report defined high reach sites as sites visited by most Internet consumers. Ad placement on high reach areas, according to the report, like portal home pages, should be complemented with buys on specialized content sites. For example, ESPN and Yahoo! Sports have the highest compositions of males between the ages of 18 and 34, a specialized audience all ad buyers should consider reaching.

The report also suggests that ad buyers monitor the audience build rate of sites but not to "buy on build alone." Content offered by Yahoo!, MSN and AOL contribute to high penetration and fast audience build. Conversely, real estate, automotive and health sites are the slowest to build audiences.

"A site's build rate is not the only measure that should be considered when evaluating performance for attaining reach. Slower building sites require longer runs, while short heavy ad runs on a sites with steel build curves is sufficient to reach the majority of users," the report says.

Overall, knowledge of audience dynamics helps online publishers and advertisers reach target groups more effectively and efficiently.