What are ad blockers and how do they work
TECH
Advertisers have been buying our attention for many centuries. Nowadays, digital platforms have become the primary way to reach customers. As a result, businesses have shifted much of their marketing to the internet. Digital advertising has become a major source of income for big tech firms. And this is the reason why these companies can provide free access to services like social media, video platforms and search engines.
Research published by the Federal Reserve Bank of St Louis shows that in the United States in 2023 alone, advertising accounted for roughly 1.3% to 2% of US GDP, while digital advertising represented approximately 0.6% to 1% of GDP. Advertising revenue generated by Google parent company Alphabet was equivalent to 0.85% of US GDP, Meta - 0.47% while Amazon represented about 0.17% of US GDP.
Due to this aggressive digital advertising, ad blockers became attractive.
What are ad blockers?
An ad blocker is a software that prevents digital ads from appearing on your screen. They block video ads, pop up ads, hidden tracking scripts that run in the background, banners ads before they load on your screen.
How do ad blockers work?
Ad blockers rely on various techniques to keep ads off your screen. Here are some of the techniques used.
Filtering lists
Ad blockers follow a set of rules called filtering lists. Filter lists also known as Blocklists work by intercepting and filtering web traffic. They then prevent ads from completing or hiding ad elements that are already loaded. They target domains, URL patterns, code snippets scripts and lists are constantly updated as new ad tactics appear.
Filtering lists are mostly written and maintained by a community of volunteers and small teams. The most well known filtering lists is EasyLists which powers major ad blockers.
2.Blocking Ad scripts.
When you visit a website, the browser loads the main page. The page also contains instructions to load additional scripts from other places. Scripts are small programs that make buttons work, load comments or handle logins. But they can also load ads, track your clicks and autoplay videos without asking. Ad blockers check the source of each script against its active filter list. If it matches the filter list, the adblocker can
Cancel the request - so the ad or tracker is never downloaded.
Return an empty or a fake response - so the page thinks the request succeeded but receives no real content.
Redirect the request to a harmless local resource, preventing contact with an ad server.
While script blocking is powerful , it can have its downsides like:
Broken website - Many sites depend on scripts for basic functionality. Block wrong scripts and you lose login features, video players or even shopping carts. The site might still load but key features just wont work.
Overblocking - Aggressive script blocking can break sites that don`t even show ads . Some sites like government sites often rely on third party scripts for legitimate purposes. Blocking them can make them unusable for no good reason.
Site owners lose revenue - When you block ads, site owners, don't get paid. For small publishers who depend on ad revenue, it can be challenging.
To avoid some of these problems as a user, you can stick to your ad blocker`s default settings, whitelist sites you trust or allow specific scripts – not the whole and the most important of all, always check for ad block updates.
History of ad blockers
The rise of ad blockers is what led to the demand and developments of ad blockers. The first web banner ad appeared in 1994, when AT&T launched on HotWired.com, achieving a 44% click through rate. As a result, other companies rushed to copy the format which soon overwhelmed many webpages. This led to slow page loading, user tracking and visual clutter.
The first dedicated ad blocker appeared in 1996, when a developer James released Internet Fast Forward. It was a plugin designed for Netscape Navigator. It was able to remove banner image ads and block tracking and cookies. However it was discontinued after Privnet the company behind it was acquired due to potential legal action concerns from online publishers.
Between 1998,and 2001, local proxy tools like webmaster and internet Junkbuster filtered ads before they reached the browser. In 2002 , Henrik Aasted Sørensen released Adblock 0.1 for the phoenix browser, later known as Firefox. Wladimir Palant followed in 2006 with Adblock Plus which introduced automatic filter list subscription. From 2014 onwards, tools like uBlock Origin, Brave and Pi-hole expanded ad blocking into privacy protection and cybersecurity.
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