Online Ad Privacy Watch: Those “Pixels” Are Tracking You [Annals of Behavioral Targeting]

In bringing the issue of what is considered personally-identifiable information more up-to-date, the FTC has finally begun to acknowledge the ever-expanding techniques used to collect information about our online experiences.   Case in point, the modest “pixel,” an invisible piece of data placed on your browser–in the words of one online ad marketer, a digital “mole.”  It’s worth reading the entire article “What a Pixel and Cookie Can Reveal,” by Brian Massey (ClickZ.  Feb. 4, 2009).  Here’s an excerpt:

The pixel delivers a list of basic attributes… These basic attributes include:

  • IP address, character set, and encoding
  • Language, connection, and host
  • Referrer, browser, and portal

The pixel can also pass along just about any information that the browser knows:

  • URL, server name, and posting method
  • Search keyword, keyword phrase, or search engine term
  • Time and date, time of day, day of the week, and week of the year

The URL provides the entire content of the page visited by the surfer:

  • Text, images, headings, and navigation
  • Parameters and values
  • Were they home or just landing?

The IP address can be used to look up more information:

  • Country, state, and city
  • ISP, cable, DSL, or dial-up
  • Bot, crawler, or spider

By adding a cookie, surfer data can be aggregated over time, and more can be inferred about visitor behaviors…

Once we get ZAG [Zip code, age, gender], we can start to segment visitors more accurately:

  • Where do they live?
  • What do they make?…
  • What is their profession, race, marital status; do they have kids; and other census data           And when we integrate this information with other non-PII databases, we can learn even more: What they buy, how often, how recently…

Author: jeff

Jeff Chester is executive director of the Center for Digital Democracy. A former journalist and filmmaker, Jeff's book on U.S. electronic media politics, entitled "Digital Destiny: New Media and the Future of Democracy" was published by The New Press in January 2007. He is now working on a new book about interactive advertising and the public interest.

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