Mozilla has released an interesting link-analysis tool (like those used for police investigations but without events) called Collusion

Collusion is an experimental add-on for Firefox and allows you to see all the third parties that are tracking your movements across the Web. It will show, in real time, how that data creates a spider-web of interaction between companies and other trackers.

I fired it up to do a simple test with a blog site. A plugin called Sexybookmarks, infamously found in “over 200,000 websites,” seemed like a good place to start. It supposedly makes it easier for readers to share posts to Twitter, Facebook, and so forth but it also gives blog administrators a vague “track performance” option.

Notice how they put a “recommended” note next to the yes option to persuade a blog owner to leave it on. Other options do not say whether they are recommended or not. Suspicious, no?

It turns out there is reason to be concerned about the “recommended” option. I clicked on yes, reloaded and Collusion immediately picked up traffic being sent to media6degrees.com.

Very easy now for any Firefox user to visualise their traffic to other hidden sites when they visit familiar ones. More importantly it shows a single central repository of user actions formed from multiple sites that present themselves to a user as separate and distinct.

You may think you are going to site Alice and site Bob, which have nothing in common, but they could actually share an innocent-looking tool that (even unbeknownst to them) sends your information off to a third-party managed by authors of Sexybookmarks who then use your “performance” data to post stories and graphs to illustrate your online behavior and interests.

Our statistics, based on aggregate search data from more than 270 million unique monthly readers reached by more than 200,000 Shareaholic publishers, reveal that Hugo is favored for Best Picture with 33% of searches…

Now the tool just needs the ability to right-click and select “block” or “deny”.