Ad Network Business Dominated by Big Players

The ad network segment of the online ad space is both vast and resilient; some estimate that there are between 300 and 400 networks still operating despite a rough economy, and the segment is littered with technology-driven upstarts.

But as the category evolves it is dominated perhaps more than ever by the Web’s biggest companies. According to the latest report issued by comScore, AOL, Yahoo, Google and Microsoft now command four of the five biggest online ad networks, and each company’s network has grown over the past year. ValueClick, which has been around for over a decade, is the only non portal/search giant to land in the top five (number 4 on comScore’s ranking with over 170.7 million unique users in December).

AOL Advertising, which of course include, reached over 187 million uniques in December, per comScore, and increase of 8 percent versus last year. Yahoo’s network also topped the 180 million mark, while Google’s ad network exceeded 178 million users—a spike of 13 percent year over year.

The fastest growing ad network over the past year was Microsoft’s recently formed Microsoft Media Network, which saw its user base swell by 31 percent to 165.5 million. The other networks exhibiting the biggest audience gains included Collective Media (+22 percent to 153.9 million users) and AudienceScience (+16 percent to  146.4 million uniques. News Corp.’s Fox Audience Network—which did not exist a year ago, pulled in at 7th place at nearly 157 million unique users.

Of course, given the sheer size of these top networks  (at least 15 networks exceed 138 million unique users, i.e. A huge chunk of the total Web audience), it is clear that most networks reach many of the same users, and likely offer inventory on many of the same Web sites. But clearly these companies’ role hasn’t diminished.

“Ad networks continue to be a powerful mechanism for delivering a large audience online, with eight different networks reaching at least 75 percent of the entire U.S. online population,” said comScore senior vp Jeff Hackett. “Increasingly, however, ad networks are improving their capability for reaching more targeted audiences as well, which delivers enhanced value to advertisers and helps sustain higher CPMs for the channel. 2010 should bring us continued innovation and performance from this growing online sector.”