Ad-blockers: definition and how do they work
What is an ad-blocker?
An ad-blocker is a built-in or manually added feature (in the form of an extension) to the browser.
The aim of an ad-blocker is to block all requests that are in any way related to tracking (whether for advertising, web analysis or affiliation).
To be more specific, ad-blockers prevent visitors from being tracked, even if they have given their consent.
The main ad-blockers on the market are Ad Block, U-Block and Ghostery.
The proportion of your traffic using an ad-blocker depends very much on your audience, its age, device and country.
How does an ad-blocker work?
An ad-blocker looks into all the requests sent by your browser. When it recognizes a request that matches certain criteria, it will block it.
To determine its criteria for blocking requests, an ad-blocker relies on lists that are constantly updated to adapt to bypassing techniques.
Here's an example of a blocking list used by ad-blockers: https://easylist.to/easylist/easyprivacy.txt (opens in a new tab)
This list contains the following strings:
.js?id=GTM-googletagmanager.comgtag/js?
If you do nothing, ad-blockers will block the Google Tag Manager and Google Analytics libraries.
Bypassing ad-blockers represents a constant watch to innovate on new techniques as blocking lists are updated.
Next step
Now that you know what an Ad-blocker is and how it can block certain requests, let's take a look at how to bypass them.