How Many Ad Companies Are Watching You?

Sixty three (63) ad networks are peeking over my shoulder right now…but I get ahead of myself.

There has been a lot of talk about Google’s recent announcement that they are rolling out Interest-Based Advertising inside of their AdWords platform. They initially began talking about this in 2009, slowly allowing more and more people to experiment with it. But, as of yesterday, it’s available to everyone.

What Is Interest-Based Advertising?

The sugar-coated answer to the question is, it is the practice of advertisers showing you ads they think will be of more interest to you based on what types of websites you like to visit. Sounds harmless right? We all know there are going to be ads on the websites we visit…they might as well be relevant to us. Well, that’s certainly one way to look at it.

The other way to look at this topic is to examine the last part of the sentence above, “based on what types of websites you like to visit.” The obvious—and to some—the unnerving question is, how do advertisers know what sites I visit?

How Do Ad Networks Track Me?

Google and all other advertising networks on the web spend a lot of time, money, and effort trying to figure out what you like to do on the web. There are many ways they track your online activities. For example, if you use Google’s Chrome browser, it has tracking built-in. When you first launch the browser, they ask if you will allow them to track your activities—most people do. (More info on opting out of this here.)

But, in general, here’s the basic process:

1. You first visit a page the ad network (Google, Bing, Facebook, and many, many others) has ads on or they have some influence over. The ad network places a cookie on your browser, which is a bit of code that allows them to begin keeping a list of pages you visit on this browser.
2. You visit more pages that contain the advertising network’s ads and the network adds those pages to the list of pages they know you’ve visited.
3. The ad network evaluates the list of pages you’ve been to and begin to categorize your interests. For example, Google has 1,000 categories that they will use to put you into. Examples of categories are “Computer and Electronics”, “Pets & Animals – Dogs”, “Arts & Entertainment – Humor”, etc.
   To see a list of the categories Google has you in, go to this URL in any browser: http://www.google.com/ads/preferences/
4. You visit yet another page the ad network is on, but this time the network displays ads relevant to the categories they think you’re interested in.

Who’s Tracking Me?

I said above there are many, many ad companies that are tracking you. Want to know how many? In the browser you use the most, visit this page: http://www.networkadvertising.org/managing/opt_out.asp

You will see a list of 75 different ad networks in alphabetical order that place cookies on browsers. And the list will already be updated to let you know which companies have cookies on your browser. For example, my browser had 63 of the possible 75 cookies in place.

A list of some of the ad networks following me

Can I Escape Interest-Based Advertising?

Yes—easily.

You can opt out of all of these cookies by using the links above. The Network Advertising Initiative gives you the tools to easily turn off all the cookies. Simply click on the Opt-Out check box for those you want to get rid of and click the Submit button.

And Google also gives you a one-click way of opting out of their cookie by again going to http://www.google.com/ads/preferences/ Google also gives you the option to customize the categories listed in your browser using this same page. Lastly Google points out that if you ever clear your cookies, the opt-out code will disappear. After you opt-out, they offer you the ultimate opt-out tool: a browser plugin that is independent of the cookie system. Simply click on the “Download the cookie opt-out plugin” button on the page that displays after opting out.

[Edit] A reader has pointed out that you can opt out of Yahoo’s tracking by visiting this page: info.yahoo.com/privacy/us/yahoo/opt_out/targeting/details.html

Is Interest-Based Advertising Bad?

The answer to that question depends entirely on you.

These systems raise legitimate privacy concerns, which is why tools and systems to opt-out exist. Many privacy advocates would prefer that you had to opt-in for such tracking rather than opt-out. And, I can completely sympathize with that point of view.

On the other side of the coin, there is the perspective that websites are going to show you ads, so you might as well stay opted-in so the ads at least have something to do with your interests. And, since the cookies are anonymous (the categories are not associated with your name, email address, or other information) so what harm do they do.

Which side of the coin are you on? I look forward to reading your comments below.

We’d like to thank 11950mike and anw-fr for generously sharing the photos above via the Creative Common’s License.