Pop-up ads and so-called pop-under ads automatically spawn new Web browser windows while people are surfing the Web that link to specific sites. For example, a person clicking through various pages on a Web portal may see a new browser window automatically appear on their screen pointing them to an online casino or credit card company.
The use of pop-up ads to inflate traffic figures has had a significant effect on some sites. Vivendi-Universal, for example, gets 54 percent of its online traffic from pop-up ads, Jupiter says.
Columbia House garnered 51 percent of its traffic from pop-up ads, according to Jupiter, and Bizrate.com grabbed 37 percent of its traffic from pop-ups.
To handle pop-up ads, Jupiter has created a new category of sites called "promotional servers," which includes individual sites that get the majority of their traffic from pop-up and pop-under ads. Those sites will not be included in the company's overall ranking of Web properties unless they are part of a network of sites that would qualify for the rankings through other means.
The move is somewhat of a reversal for Jupiter. It had defended the practice of including pop-ups, saying it made its results more consistent. Competitor Nielsen/NetRatings, which agreed to acquire Jupiter for $71 million in October, had excluded pop-up ad traffic from its rankings.
AOL Time Warner led the way in the general Web property rankings for November, with 83.8 million unique visitors. It was followed by Microsoft's MSN Network, with 74.7 million visitors, Yahoo with 71.9 million visitors, and Terra Lycos, with 38.2 million visitors.
In fifth place, Vivendi replaced Webcam seller X10. X10 was one of the first companies to use pop-up ads in a big way. But with the new ranking protocol it dropped out of the top 50.
Jupiter also said Wednesday that it would begin ranking different channels of portal sites. It now compares, for instance, the business and finance, real estate, and travel areas of America Online, Yahoo and MSN, among others.
AOL led the finance and e-mail categories, ahead of Americanexpress.com and MSN Hotmail, respectively. About.com was the most popular news and information site, while AmericanGreetings.com topped the electronic card category, Homestore.com ranked first in real estate and Mapquest.com was the No. 1 travel site.