Ad block

Ad blocking is the practice of blocking advertisements, typically through automated means. Typical goals for doing this are reducing distractions, lowering the extent of data collection, decreasing resource usage (battery, network traffic, memory) and avoiding security threats that leverage advertising networks.

Consumer impact summary

Ad blocking is the crux of one of the most prominent conflicts around right of ownership, where users feel justified in deciding what their devices do or don't, while platforms that rely on advertising, especially those that offer free services to users, argue that advertisements sustain the platform and must remain untouched. Some platforms even actively detect ad blocking in order to display a relevant notice or to degrade functions of a service. This has turned into an arms race between advertisers and consumers.

Advertisements are increasingly showing up in devices (e.g., refrigerators, cars, televisions) built right into their system software, making ad blocking difficult.

There are efforts to use copyright law (e.g., DMCA/Spotify/Revanced, and German court case) to force consumers to play ads or run other programs on devices.

Lea Verou claims that ad-blocking is theft, and Linus Sebastian claims it's piracy. Christian Heilmann and Doc Searls say that acceptable and non-tracking (de-personalized) ads should be incentivized in order to reduce intrusive ads.

Technologies

Diversity of advertisements has prompted the use of diverse technologies to block them.

Web browsers

Web browser extensions that block ads are some of the most popular extensions, some browsers even have ad blocking built in. This is likely in response to advertising overload that has made the Web difficult to use prior to their inception. Obtrusive advertising has remained to be a problem to this day, and continuous evolution of ad blocking in web browsers in response has produced what is probably the most prolific ad blocking culture today, leveraging openness of the web platform.

Web's openness, however, is threatened by Google's dominance in the web browser market. A change to browser extension interfaces in Google Chrome browser, broadly known as "Manifest V3", and support for older interfaces phased out across 2024-2025, has made Chrome incompatible with uBlock Origin, one of the most popular ad blockers for the web, as well as hindering functionality of numerous other browser extensions. This act prompted the creators of uBlock Origin to develop uBlock Origin Lite with less comprehensive blocking features, but compatible with Chrome's new extension interface. The Electronic Frontier Foundation considers this change "another example of the inherent conflict of interest that comes from Google controlling both the dominant web browser and one of the largest internet advertising networks" and "outright harmful to privacy efforts". The regular, fully featured version of uBlock Origin remains available and in active development for other web browsers such as Firefox and Opera.

Network level

Installed by a network's administrator or into a device's operating system, such solutions provide access to the internet through a filter that blocks communication with ad platforms, forcing them to function as if access to the internet is unavailable. This typically prevents them from functioning, as ads have to be downloaded from the internet in order to be displayed.

This technology makes it possible to block ads even on devices where software does not allow this function, but does connect to the internet through means provided by the user. Control over the means of internet access is what makes this possible.

For example, Pi-hole and AdGuard Home are installed as DNS servers for the local network (typically a single router at home), while AdGuard and RethinkDNS provide a similar effect on one device (and not the rest of the local network) where users can install applications of their choice.

It's not a perfect solution as it is only able to detect and block ads that are served through infrastructure that is separate from the rest of the application or service. Implementing it this way makes it easier to integrate ads into software, which is why this is often the case and a reason why this technique is effective.

Application specific

Some ad blocking technologies are limited to specific applications.

One of the most popular examples of this is Sponsorblock for YouTube, which combats "ad integrations": advertising segments embedded by authors of the content directly into their YouTube videos, which makes ad detection (and consequently blocking) difficult.

Another technique, available where users are able to install applications of their choice, is partial reverse-engineering and modification of applications that include advertising functionality, to block or remove that functionality. This technique is strongly associated with piracy, since the same method can be used to force a commercial application to function without a license through removal of a license check.

Response

A lot of platforms that host ads do not react to ad blocking at all and function normally without ads.

Some platforms, however, employ active measures to prevent ad blocking through various means:

Coaxing the user

Example of an anti-adblock pop-up resembling the "consent-or-pay" tactic.

Some websites detect ad blockers and introduce inconveniences and defects on their platform in response when that detection is tripped.

One common response to detection of an ad blocker is display of additional pop-ups & overlays about it. Messages displayed through techniques like this range from humble requests to turn the ad blocker off to Consent-or-pay demands.

A less conventional approach is a built-in option to disable ads available on some condition such as an active paid subscription or a certain amount of user contribution to the website, e. g. Stack Overflow offers such an option for users with a high enough reputation score.

Technical complications

Some websites obscure the website's markup in a way that, depending on the extent of obscuration, either makes popular rules ineffective or makes it impossible to build consistent rules to identify ads at all, e. g. by randomizing the values of class attributes in HTML or mixing ads in with useful content.

It's an engineering challenge for advertisers, since modern ad blockers come with many mechanisms for targeting ads, and most jurisdictions have legal requirements for ads to be explicit, constraining the end result to something that is both properly displayed and legally labeled as an ad.

This can turn into an arms race between the developers of ad blockers and the ad platform, where blockers can offer a hard fight, but a sufficiently resourceful ad platform can win, e. g. uBlock Origin stopped supporting ad blocking filters for Facebook in August 2026.

See also

• Bloatware

Further Reading

• Advertising overload
• Ad blocking on Wikipedia