# Definition of Ad-Blocker

An ad-blocker is a built-in or manually added extension to a web browser designed to block requests related to user tracking. These requests can include advertisements, web analytics, and affiliate tracking.

**Objective**

The main goal of an ad-blocker is to intercept and block all requests associated with tracking technologies, even when the user has explicitly given consent. This includes:

* Advertisements (banners, videos, etc.)
* Data analytics scripts
* Affiliate mechanisms

**Impact**

Ad-blockers directly affect visitor tracking and analytics tools, reducing the ability to collect accurate behavioral data. As a result, marketing or advertising campaign statistics may be skewed due to the absence of certain users in the reports.

**Main Ad-Blockers**

Here are the primary ad-blockers available on the market:

* AdBlock
* U-Block Origin
* Ghostery

**Usage Variability**

The rate of ad-blocker usage within an audience depends on several factors, such as:

* User age
* Type of device used (computer, mobile, tablet)
* Country of origin of the audience

These factors significantly influence the proportion of visitors blocking ads and other forms of tracking.