I’ve been reading Eli Pariser’s book The Filter Bubble and was fascinated by his description of how data collection companies operate. Independently of that, David Ascher suggested that I add a feature to the Hackasaurus goggles which helps learners understand how cookies and tracking works.

I actually didn’t know a lot about tracking myself, so I whipped up a Firefox add-on called Collusion to help me visualize it better. The results were a little unsettling.

I’ve put a demonstration up at, which takes you through five popular websites and visualizes the data collection companies that track you across them. From there, you can download the add-on if you want to see the tracking visualization of your own browsing behavior evolve in real-time.

Special thanks to the Mozilla Add-on SDK team for making a great foundation to build on. This experiment also gave me a chance to play around with d3.js, which is a fantastic successor to Protovis. And thanks to PrivacyChoice for their excellent tracker list, which I’m sort of using without their permission. I hope that is okay.

I’m also not really a privacy expert, so I’m not sure if everything I say in the demonstration is completely true. If you find any inaccuracies, please let me know.

Finally, if you need the source code, it’s all at I’m particularly interested in seeing better visualizations than the force-directed graph I’m using, which regrettably requires a lot of user interaction to explore and understand.

38 Responses to “Collusion”

  1. Chris McAvoy Says:

    Don’t forget about all those fancy like buttons and analytics thingees and social comment systems. Great visualization, this is important stuff to realize. We’re all big bags of meat with credit cards to these companies.

  2. Abhinav Sharma Says:

    This is pretty awesome! I was thinking of writing this myself, glad I found it first 🙂

  3. perry Says:

    what i fail to understand is how can extensive tracking of my web activities harm me in any way? doubleclick knows i frequent sites a, b, and c. big deal. and in return it gives me better ads. i really don’t see any reason for alarm.

  4. maiki Says:

    Perry, check out It goes over what happens, and includes links to cases of each step happening.

  5. Taliesin Beynon Says:

    Sweet idea. And I thought I recognized d3’s silky smoothness…

  6. Twan Says:

    Great tool, shocking results.

    May be a slightly different treatment of the domain names would make even more clear.
    Currently sdomain names postfixed with or are heaped into a single one.

  7. Robert Says:

    I would love to see a Chrome version of this extension! Visualizations are key for teaching these kinds of concepts, great work.

  8. ben Says:

    Cool stuff!

  9. vinoo Says:

    Yes, I have followed the link and installed the add on in my Firefox. Now what? What am I supposed to DO to see whatever it is I am supposed to see?????

  10. jwriter Says:

    Sorry, it is very unclear what collusion actually does. If I use Ghostery or other addons, what does Collusion actually display? It is vague to say that Collusion shows “entities that track your behavior across the web”. Does Collusion display these entities even if a user has cookies or javascript disabled? So please put in your description: Does Collusion display entities that are are attempting to track you or entities that are actually receiving information about you (the latter is more useful). Thank you.

  11. Big Brother Says:

    Nice, but

    A) pleaase support FF 3.6 – at least as long the annoying memory leaks are still in newer FF versions

    B) please not only visualize, but also BLOCK them!


  12. Anon Says:

    Edit your “hosts file” (Windows, Linux, Mac) to redirect the tracking domain names to and you are done… without installing any add-on.

    As a bonus, you will surf faster since most adds will be blocked.

  13. jwriter Says:

    Thanks anon, appreciate the suggestion. It looks pretty easy to edit the hosts file. For OS X there is an application called NetInfo Manager. My questions are: 1) where do I obtain a list of tracking domain names and 2) how do I keep this list current? Thanks!

  14. Vincent Says:

    jwriter, there are a couple of websites that publish a hosts file for these kind of things…. is one of them that is updated frequently

  15. anon_ms Says:

    For those of us less technically inclined, some instructions on how to use the tool would be helpful. I installed the add-on but have no idea how to see the visualization.

  16. Gert Says:

    Thanks, nice stuff 🙂

    After using collusion for about half an hour I decided that it’s high time to put Google and Facebook on a diet (using a couple of ABE user rules). This together with “keep cookies until I close FF” and with the Flash cookies conveniently located on a RAM disk should help to increase the “new user” count on most web sites 🙂

    Btw: for some reason is the centre of all the otherwise tidily disjunct subnets, and thus is emulating Doubleclick. Is there anything I can do about that ?

  17. Paolo Says:

    Great work, thanks.
    Any chance your add-on could work for opera, too.

  18. heems Says:

    What to do after installation: type in your browser and note that all the websites you are visiting are displayed, as well as the marketing-thugs following you.

  19. Paolo Says:

    Actually this was a question, forgot question mark.
    So, any chance your add-on could work for opera, too?

  20. bucket of espresso Says:

    Reminds me of TheyRule…but very slick, initial impression was that the animation should be a little quicker.

  21. Redback Says:

    Doesn’t seem to work for me but then again with privoxy + ghostery, who know where to start with, when solving the issue with this product , trying it out to see whats what.

    P.S does this product rely on the various cookies and the a likes ?

  22. AnnaZed Says:

    Hi, I got the add-on and was really perversely enjoying how huge my little net was getting. Cool visual. I’m not sure what if anything I am going to do about this information, but I like having it. I also posted your ad-on and a like to your site on my facebook.

    So, now I have a problem though. I have rebooted a few times and the thing just started weaving its web again, but this reboot I now have this message on the linked page:

    Since you don’t seem to have the Collusion Firefox Add-on installed … etc”

    but I do!

    What happened?

  23. Carolo Says:

    I’m very interested in the answer to Gerts question:
    Why is also appearing in this graph?
    Could you please answer this question?


  24. Hijacking Your Filter Bubble – on — Viewser Says:

    […] If you use the Firefox browser – there is a really cool tool to help you visualize who is tracking you and at what sites, called collusion. […]

  25. OWP32: Eingekreist | Der deutsche OpenWeb-Podcast Says:

    […] angeknackst Ghostery Collusion undeletable cookie via […]

  26. Kevin Flavin Says:

    Excellent tool. Even marketing people need to know how this works, and the impact and persistence across the interwebs, to help us make good decisions for our customers. If we’re uncomfortable with it, it’s not a good idea for them either. Thank you for this.

  27. Hijacking Your Filter Bubble | Viewser Says:

    […] – there is a really cool tool to help you visualize who is tracking you and at what sites, called collusion. This may help you see the astounding number of companies who watch and share your moves around the […]

  28. Mozilla Labs » Blog Archive » Watchdog: Visualize your password reuse Says:

    […] This way, you can quickly see which passwords you’re overusing and need to change. Hat-tip to Collusion, another interesting Firefox add-on with roots in Mozilla Labs, for inspiring some of my thinking […]

  29. xenomancer Says:

    This is an awesome add-on! I’ve known about such tracking for a while, but the visualization makes it really stand out. Have you given any thought to making a similar add-on for chrome? It would be very much appreciated if you were to do so. I haven’t been able to find any similar projects in the “chrome web store” that can compete with what I’ve seen you do for firefox. Thanks again!

  30. Firefox Add-On Collusion Shows Who’s Tracking You Online « « Fix-Singh - Gadget RepairsFix-Singh – Gadget Repairs Says:

    […] behavioral tracking advertisers. Collusion was originally developed as an independent project by Mozilla engineer Atul Varma. Mozilla is now developing the add-on with the support of the Ford […]

  31. Mozilla’s Collusion plug-in aims to expose online tracking Says:

    […] to explicitly identify sites that engage in behavioral tracking — Collusion’s developer admits to “sort of using without their permission.” Collusion is also providing access to […]

  32. Dominic White Says:

    Tracking the Trackers (my mods to the Collusion AddOn)…

    In July last year, Toolness, released a cool Firefox add-on, named Collusion, that draws a pretty visualisation of who’s tracking you as you visit different sites. It gained some popularity after Gary Kovacs, Mozilla CEO, showed it off in his TED talk…

  33. Some1 Says:

    Umm.. it seems that this plugin is actually saving my cookies when I explicitly remove all of them (clear @ end of session). If I clear all cookies, then look @ collusion’s graph, everything that was tracking me prior to the clear all is back in my list of cookies.

    I uninstalled collusion and cleared all and it now stays that way between start/quit of firefox sessions..

  34. Collusion for Firefox: Who’s tracking you? | Digital Transparency Says:

    […] cookies you pick up as your travel around online.  Initially developed by an engineer at Mozilla, Atul Varma it’s now being taken further by the company, with the not insignificant support of the Ford […]

  35. Do not track vs. don’t track « mathbabe Says:

    […] But don’t believe me, visualize your own cookies as you travel the web. The guy (Atul Varma) who wrote this also open-sourced the code, which is cool. See also the interesting conversation in comments on his blog Toolness. […]

  36. Handelskraft – Das E-Commerce und Social-Commerce-Blog - Webtracking-Tracker Collusion von Mozilla Says:

    […] getrackt wird. Um herauszufinden wer das genau macht, gibt es jetzt ein neues Firefox-AddOn aus dem Hause Mozilla-Labs. Die Erweiterung „Collusion“ gibt Aufschluss darüber wie viele und vor allem welche Firmen […]

  37. New Mozilla Firefox Plugin shows which sites are tracking you and why - fixedByVonnie Says:

    […] These shocking facts imbued Varma with a desire to see how third-party sites were connected so he started implementing an experimental Firefox plugin called Collusion to help the world understand how data tracking works.  He candidly describes his light bulb moment on his blog. […]

  38. Lightbeam(Collusion) – Firefox Add-on | Tech Morphism Says:

    […] began in July 2011 as Collusion, a personal project by Mozilla software developer Atul Varma(Blog | Collusion). Inspired by the book The Filter Bubble, Atul created an experimental add-on to visualize browsing […]