Think of the Web as one big vacuum, sucking up every bit of information possible from the sites you visit, the things you click, the little bit of bio you might provide (log-in name, birthday, income, hobbies, favorite movie, etc.) Then put all that information together, where it can be used to create a specific profile of you and others like you. It's the Holy Grail of advertising, targeting an ad message for small affinity groups or even one specific individual.

A new study was released Tuesday about this increasing trend towards person-specific ad messaging. The trend is called “behavioral targeting,” and it’s quickly becoming the norm in Web advertising.

The study is by a Stanford University computer scientist, Jonathan Mayer. Mayer found that Web sites are widely sharing your log-in name and personal information. The information is sent to companies that aggregate information about you and sell it to advertisers. The aggregation is getting so specific that you may receive an ad from a manufacturer for a sump pump based on where you live (it rains a lot), your house design (you have a basement), and the fact you clicked a link on a Home Depot site (for water sealants).

The ability to collect all this information and build individual profiles is worrisome from a privacy standpoint. Simply put, if you cruise the Web, you might as well give up the idea that you’re anonymous. Indeed, the opposite is true – you’re more public than you’ve ever been.


Read a National ACLU blog post on "behavioral targeting" by Liberty and Technology expert Christopher Calabrese.

Visit the ACLU of Northern California's Demand You dotRIGHTS Web page.

Read about national media expert Jeff Chester's talk last month in Burlington on Digital Media at the Crossroads (story by reporter Andrew Nemethy at Chester is executive director of the Center for Digital Democracy in Washington.