How To Find Out Who Is Tracking You On The Web With The Firefox Add-On Collusion

When you surf the web I’m sure you are aware that your browser stores something known as cookies. These cookies are often used to store settings, such as your user name or preferences, and can save you a bit of time when you revisit sites you’ve been on before.

Cookies can also be used to track you around the web though, typically to enable advertisers to target you with adverts that you are more likely to buy from. And you may just be surprised at just how many of these cookies are tracking you and how many web sites they are linked through.

Well now you can find out how you are being tracked with a visual guide called Collusion which is an add-on for the popular Firefox browser.

[box type=”info”]To get started, visit

On the left hand side of the screen is a grey box from where you can watch a demo of collusion in action. At the bottom is a link to install the add-on. Click on that.[/box]


You’ll see a Window like the one above appear, asking you to confirm if you would like to install the add-on. Its ok to do so; the author, Atul Varma, is a Mozilla Labs employee.


Once you have the add-on installed into Firefox you will see a tiny icon in the bottom right hand corner of your browser.

[box type=”info”]Click on this to start your visual demonstration of how you are being tracked on the web.[/box]

The screen will be blank at first so visit a few sites:


The image above was generated for me after I visited just a few web sites.

The grey dots signify legitimate cookies that store settings whilst the red dots refer to tracking cookies. The grey lines will show you how many of these tracking cookies are interlinked between the various web sites that you visit. In the example above you can see how one site I visited did not use any tracking cookies at all and that is why it is not linked to the others in any way.

If you do see red dots then you can hover your mouse over them to discover what they are and how they connect between the various web sites that you have visited. In the example above you can see how Google’s has followed me over more than one web site.

Collusion is a useful add-on that will give you a quick and easy to understand guide to how cookies are being used to track you around the web. As you can imagine, the aim of most of these is to deliver highly targeted advertising to your browser in the hopes that you will part with some money.

Do not track

The major browsers have a feature built into them to allow users to opt out of such tracking but this can be a bit hit and miss as there is no legal requirement as of now for advertisers to honour it.

To turn on Do Not Track in the main browsers perform the following task(s) depending upon which browser(s) you use:

[box type=”info”]For Chrome download the Keep My Opt Outs add-on:[/box]

Do not track Chrome

[box type=”info”]For Firefox go into your browser and click on Tools > Options > Privacy and then tick the checkbox next to where it says, ‘Tell web sites I do not want to be tracked'[/box]

Do not track Firefox

[box type=”info”]For Internet Explorer 9 visit the Microsoft Do Not Track Test Page and download the tracking protection list.[/box]

Do not track IE9

What are your views on Collusion and tracking on the web in general?

About Lee Munson

Lee's non-technical background allows him to write about internet security in a clear way that is understandable to both IT professionals and people just like you who need simple answers to your security questions.

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