That’s where Tracker Watcher comes into play. The Firefox add-on will analyze the active website for trackers and display all that have been found on an external page. It provides information about anonymity, sharing of information, Sensitivity and deletion in an easy to understand manner.

• Anonymity: Is the data anonymized or tracked across websites?
• Sharing: Do they share the information with third parties?
• Sensitivity: Do they use the information in sensitive personal areas like health conditions or financial matters?
• Deletion: Do they promise to delete the information?

Links to privacy statements of trackers are provided if available. Some trackers are not included in the list but are listed below the table. This could mean that the service does not have enough information yet about those trackers so that they could not be added to the table.

The very same page links to opt-out pages for advertisers that support that option. Those links lead to the website of the developer of the tracker where the opt-out can be announced. The Tracker Watcher website contains another link to a global opt-out page to opt out of all 91 companies that have been analyzed by the service or only 71 of those companies that have raised concerns.

Tracker Watcher can be downloaded from the Mozilla Firefox website.

One way to do that would be to block cookies of those Internet advertising networks. It also works to clear cookies after every session but there is a better way. Many Internet advertising networks are providing ways to opt-out of behavioral targeting by setting so called opt-out cookies on the user’s computer system.

If an opt-out cookie is present they will not track and analyze the user by placing additional cookies on his computer system. The major problem here is that there are hundreds of online advertising companies that use behavioral targeting in some of their advertising campaigns.

A user following that manual approach would have to locate the website of the Internet advertising network and there the page where the opt-out cookie could be set. This would take days and the chance would be high that a lot of networks would be missed.

Privacy Choice was mentioned in yesterday’s post about Google’s new behavioral ads. The website provides the means to opt-out of behavioral targeting of dozens of ad networks including major ones like Google AdSense, DoubleClick, Yahoo! and AOL.

A click on the opt-out button on the main page of Privacy Choice will set all opt-out cookies that are currently provided by the service. This may take up to a minute as several connections to the various internet advertising agencies are established to set the cookie.

The only thing that you need to be aware of is that the opt-out cookie is a normal web browser cookie that will get deleted if you clear all of your cookies. You would need to set the opt-out cookie again after clearing the cookies of the web browser.