Watch Out for Online Ads That Watch You

You can keep at least some behavioral-ad cookies at bay by opting out of the services at the Network Advertising Initiative's site.
You can keep at least some behavioral-ad cookies at bay by opting out of the services at the Network Advertising Initiative's site.
Online ads are not only booming--and scrolling, spinning, shaking, shouting, and singing--they are also watching you even as you are viewing them, capturing your click patterns to create more detailed profiles than traditional browser cookies do.

Behavioral marketing networks such as BlueLithium, Revenue Science, and Tacoda display ads based on your browsing habits. Spending on these behavioral ads will grow from $1.5 billion in 2007 to more than $2 billion next year, according to eMarketer, a market research firm. And the company expects video ads to account for more than a third of that total.

The networks say that behavioral ads are more effective for advertisers, and usually less intrusive for consumers, than are standard pop-ups or adware. But the potential for abuse is troubling, privacy advocates claim, and the vast majority of Netizens have no idea that their actions are being tracked so closely.

Visit any of the 1000-plus sites on BlueLithium's ad network, and your PC will get a cookie that records the Web pages you visit, the ads you click, and whether you bought anything. The network then delivers ads based on your interests: Shop for cell phones at one site, and you might see ads for handsets at another, unrelated site, while someone with other interests would see a different ad. Unless you keep a close watch on your browser cookies, though, you'd never know you were being targeted. BlueLithium chief marketing officer Dakota Sullivan declines to name any of the company's clients, but says that they include 70 of the 100 most popular sites.

Sneaky Cookies

Last November, the Center for Digital Democracy and the U.S. Public Interest Research Group filed a 50-page complaint with the Federal Trade Commission, claiming that such techniques by behavioral ad networks were unfair and deceptive marketing tactics.

"There's nothing wrong with serving an ad targeted to what users are interested in," says Jeff Chester, the CDD's executive director. "But you need to tell consumers exactly what you're doing and get their permission before you follow them from site to site."

Shortly after the complaint was filed, Tacoda said that it would periodically run ads on its network disclosing how it uses tracking cookies, and that it would set the cookies to expire after a year.

The Tacoda site features a prominent link to the Network Advertising Initiative's opt-out page, where consumers can turn off the tracking cookies from Tacoda, Revenue Science, and five other online ad networks (click on the thumbnail screenshot at the top of this article for a view of this page). NAI executive director Trevor Hughes says that, in addition, consumers can protect themselves by reading privacy policies and by carefully managing their cookies.

Revenue Science chief executive officer Bill Gossman says the way his company captures Web surfing data makes it "nearly impossible" to merge clicks with users' personal information. "If a new corporate owner, the government, or anyone else asked us to provide data on an individual user, we most likely could not do so," he says.

BlueLithium's Sullivan claims that linking a person to a surfing history would be relatively easy for companies with information on both, but doing so would ignite a firestorm of public criticism.

Database Risk

As Web entities continue to consolidate and corporate giants such as Microsoft enter the behavioral ad business, consumer advocates fear that the razor-thin boundaries between anonymous clickstreams and personally identifiable data could dissolve.

The risk? "Once a database exists, people often dream up ways to use it," says Peter Swire, an Ohio State University law professor and former privacy advisor to the Clinton administration. "Notice and effective choice by consumers are the way to go."

Dan Tynan

To comment on this article and other PCWorld content, visit our Facebook page or our Twitter feed.
Shop Tech Products at Amazon