Today Google launched its behavioral targeting ad program, which it calls "interest-based advertising." This move has been widely expected once Google completed its $3.1 billion acquisition of DoubleClick one year ago today.

The issues with behavioral advertising have been with us for over a decade (DoubleClick was founded in 1996, and privacy issues soon followed), and have grown as more people use more services online and more information has become available about your online behavior. Many, including EFF, are concerned about behavioral targeting because it means that information about how you use the web is collected, stored and associated with a cookie on your browser, which can track you across different websites and online services. One way to help protect your privacy is to clear cookies regularly. However, this is insufficient, because a new cookie would be written the next time your browser loaded a banner ad.

The most privacy protective solution would be to have behavioral targeting systems be based on the user's opt-in. To no one's surprise, Google has not gone down that road ("'Offering advertising on an opt-in basis goes against the economic model of the Internet,' Google spokesperson Christine Chen told the IDG News Service"), and we are not aware of any major player in online advertising that has an opt-in targeting system. Google has, however, done some things that make opt-out quite a bit better.

Google contacted us about behavioral targeting early on in their development process, and solicited our feedback. One issue we discussed was a persistent problem with opting-out of targeted online advertising -- the use of cookies to opt-out of tracking cookies. The problem is that the very users who care most about privacy are the ones most likely to delete cookies. Yet, if a user deleted all their cookies, they would also delete the cookie that had opted them out of the targeting.

So we worked with Google to seek a new solution. Google accepted the technical challenge, and the result is the Advertising Cookie Opt-Out Plug-in, which allows users to keep their opt-out status for a particular browser even when they clear all cookies. We appreciate that Google was responsive to the opt-out cookie concerns, and especially pleased that the plug-in is available as an open source project. We look forward to it being available for Safari, Chrome and other browsers, not just IE and Firefox.

Google also introduced its Ad Preferences Manager tool. While using this tool does not stop Google from tracking users, it allows users to express preferences about what sort of advertisements will result from that tracking. We prefer to opt-out, but this is an improvement to transparency.

If you are a user who shares our concerns about privacy, we encourage you to opt-out of tracking and keep regularly deleting your cookies. Just as critically, we encourage Google to promote the opt-out options prominently, and make it simple and easy for an average person to use. After all, these tools are not useful if no one uses them. Keep in mind that the plug-in works only on particular browsers, so you will need to install it on every browser you use.

This may not be the end of the story. Last month, the FTC revised its Online Behavioral Advertising Principles. Last year, the House Energy and Commerce Committee looked at online advertising practices, and Rep. Markey said "he and his colleagues plan to introduce legislation next year [i.e. 2009], a sort of online-privacy Bill of Rights, that would require that consumers must opt in to the tracking of their online behavior and the collection and sharing of their personal data." We expect that government policy-makers will continue to look at behavioral advertising for the next decade.