Your Ad Blocker May Be Helping Advertisers To Target You

A French study has shown that even though your ad blocker may be stopping unwanted adverts, it could also be identifying you to advertisers, thus making you more likely to be targeted in future!

The Study

A recent online study by French researchers Inrialpes, which builds upon previous EFF research from 2010, has shown that the Browser Extensions (including ad-blocker extensions) you have, and “Login-Leak” i.e. details of the (social media) websites that you have logged-in to as identified by your browser, can mean that advertisers can piece together the information to identify you. This could mean that even though (and partly because) you have an ad blocker (extension) in place to protect you from unwanted adverts and slow page downloads, you can be easily and accurately identified by advertisers, which could lead to targeting by them.


The research identified how several elements can be combined to create a clear, unique, identifiable online fingerprint of you to advertisers, even if you clear your cache or take other privacy-protecting measures. The suppliers of these elements were found to include:

  • Third party cookies that track you and can be identified when you arrive at other sites where the same advertiser’s cookies have been placed.
  • Information about your browser’s configuration e.g. version, language, timezone.
  • Data given via an estimated 13,000+ browser extensions. This could include ad blocker extensions. This data can be obtained by exploiting websites that can access browser extension resources.
  • Information gained about what kinds of plug-ins you are using.
  • Information gained using re-direction URL hijacking about websites that you are logged into e.g. social networks like Facebook,
  • Instagram and Twitter, plus other websites such as Amazon, Gmail and Airbnb.
  • Information gained via the Content-Security-Policy (a security feature that limits what the browser can load for a website).

This kind of information and the web user identity profiles that it helps to create have a value to advertisers, and to those selling advertising space.

What Does This Mean For Your Business?

Business time, resources, and security are important and there are steps that you can take to preserve these by making yourself less likely to be identified via the methods described. Technical commentators suggest that you can use Mozilla’s Firefox browser because it is less “leaky”, make sure that you log out of your social networks and other websites e.g. Amazon when you’re not using them, and use "private browsing" / "browsing in incognito" mode.

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