What Is Adblocking?

Date First Published: 10th December 2022

Topic: Web Design & Development

Subtopic: Web Technologies

Article Type: Computer Terms & Definitions

Difficulty: Medium

Difficulty Level: 5/10

CONTENTS

Why Do People Use Adblocking Software?
How Does Adblocking Work?
Controversy Of Adblocking

Learn more about what adblocking is in this article.

Adblocking, also known as ad filtering is a software capability for preventing online ads from displaying in a web browser by blocking requests to ad servers that deliver the ads. This may be accomplished by browser extensions, such as Adblock or a software program installed on the computer designed to block ads in a specific web browser. Adblocking removes or alters all advertising material displayed on a webpage.

Why Do People Use Adblocking Software?

The reasons why people use adblocking software are:

Improved page loading times - When using adblocking software, it blocks all video, popup, sticky, interstitial, and banner ads from appearing on the page, making the page load faster.
Privacy protection - Ads can follow people around and change their content based on people's behaviours, such as what they visited before and their browsing history. Some people feel like personalised ads is a privacy issue.
Malvertising protection - Some ads can spread malware that harms computers. These may unexpectedly redirect users to malicious websites or perform a drive-by-download. However, adblockers do not replace antivirus software and they do not fully protect a computer from viruses and malware.
Saving bandwidth - The ad code and content will consume bandwidth each time it is downloaded for a user. Obviously, the fewer times the ad is downloaded from the ad server, the less bandwidth it will consume.
Better user experience - Some ads, especially ones that cover the whole page and appear after another one has been closed can be intrusive to users and disrupt their experience. In some cases, the ads might make a website unusable. The blocking of ads will result in less cluttered pages and fewer distractions.
To save battery on mobile devices and laptops, since less content will need to be downloaded.

How Does Adblocking Work?

Adblocking technology relies on filter lists (e.g. EasyList) to known ad servers that determine what to block and hide and what to allow to appear on a page. The filter lists simply consists of URLs in the form of an allowlist and a blocklist. Every time a website is visited, the adblocking software checks if one of those URLs is in the filter list. If it is, the request for the content is blocked and the ad is not downloaded onto the webpage. Filter lists are usually maintained by a third party that is not affiliated with the developers of the adblockers.

Although the filter lists contain URLs of known ad servers, it is not possible to block requests to every single ad server. Therefore, most adblockers also have functionality that can detect the behaviour of an ad and block it.

Controversy Of Adblocking

Website owners often use ads to fund their websites. Some website owners are unhappy with people using adblocking software as they don't get any ad revenue from people who don't see their ads. Even though websites such as The New York Times and The Daily Telegraph have successfully implemented subscription and membership-based paywall systems for revenue, a lot of sites rely on advertising to generate revenue. Some website owners may have functionality on their site that can detect adblockers and may display a message asking them to disable it if it detects one. Sometimes, website owners may even block users from viewing a page if they have an adblocker by displaying an overlay that covers the content and asks them to disable their adblocker or restrict access to certain features if they have an adblocker, which is highly controversial.