What Marketers Need To Know About Ad Blockers

Online Advertising Article
20 mins

Ad blockers could be affecting more than just your ad revenue. In fact, these widely-used applications affect many aspects of marketing, from audience measurement to user experience.

This guide covers the key things marketers need to know about ad blockers: what they are, how they work, and how you can factor ad blocking into your strategy.


What is an ad blocker?


An ad blocker is a web browser extension, smartphone app or other application that prevents advertising features from appearing as intended in a user’s web browser.

When someone using an ad blocker navigates to a webpage, their ad blocker searches the page for advertising-related scripts or links before the webpage loads. If an advertising script or ad-related domain is detected, the ad blocker stops the browser from loading the relevant feature of the webpage.

Ad blocking can lead to a greatly altered user experience of a webpage that’s intended to feature ads, often leaving parts of the page blank.


How widely are ad blockers used?


Pretty much wherever you are, a huge share of internet users are blocking ads. You may well be using an ad blocker yourself.

According to Statista, 35.2% of internet users in the UK were using an ad blocker in Q3 2020. High as that percentage may seem, it’s actually lower than the average global ad blocking rate, which was estimated at 42.7% in the same period. In Indonesia and India – the countries with the highest rates of ad blocking – over half of internet users were found to be using an ad blocker.

Prominent ad blockers include Adblock Plus, AdLock, Ghostery, Privacy Badger and uBlock Origin.



Why do people use ad blockers?


You may or may not think that removing ads from a page will improve its user experience. Either way, large numbers of people choose to use ad blockers – so clearly, it’s a widely held view that the internet is best experienced with an ad blocker.

Think With Google proposes the following categories of people who use ad blockers:

  • People who install ad blockers to protect their privacy
  • People who simply don’t want to see ads
  • People who don’t realise they’re using an ad blocker (e.g. family members using a shared computer)
  • People who are overwhelmed by intrusive, annoying ads

It’s reasonable to assume some overlap among these categories. For instance, a person who wants to protect their privacy might also feel overwhelmed by intrusive ads.


What do ad blockers actually block?


Ad blockers might be blocking more features of your website than you think. Some of the features that can be blocked by popular ad blockers include:

  • Ads, obviously! Not all ads are automatically blocked by ad blockers, but many are. The ad types most likely to be blocked include banner ads, video ads and popups, and others which can be considered especially disruptive to web users.
  • Tracking scripts, such as Google Analytics tracking code snippets and Facebook tracking pixels.
  • Other third-party scripts.
  • “Annoyances”, such as cookies notices and mobile app banners.
  • Social media features, such as widgets, share buttons and other icons.
  • Security threats, such as malvertising[https://www.imperva.com/learn/application-security/malvertising/] and malicious cryptocurrency mining.

Thankfully for webmasters, not every ad blocker affects all of these features, and many ad blocker users are selective about which features they do or do not block.

For a more in-depth overview of how ad blockers work, read Intego’s article: Ad-Blockers: The Good, the Bad, the Ethics.


Why some ads can get past ad blockers


Ad blockers can be surprisingly flexible about which ads they block. Some ad types and ad providers are whitelisted by default in the user’s ad blocker settings. This is ostensibly because the ads meet quality standards designed by organisations such as the Acceptable Ads Committee (AAC) – but it could also be because the advertiser has paid the ad blocker to allow its ads.

If you don’t want to pay or abide by the rules of the AAC, another way to dodge ad blocking could be to create bespoke ads. Technically, most ad blockers block the web requests used to download ad content onto a webpage, rather than blocking ad content itself – so you can get past them with bespoke ads that have no connection to websites likely to be blacklisted by ad blocking services.


How do ad blockers affect marketing data?


Ad blockers can affect your website data in various ways. Understanding these effects will help you to interpret your website analytics more accurately.

The most important thing to know is that some ad blockers can block tracking codes that gather data on the people who visit your site. This prevents analytics tools such as Google Analytics from tracking those users – so the users’ activity won’t be measured and reflected in your website data, in the usual way.

Let us clarify here that not all ad blocker users will have tracking prevention activated. But a significant minority will.

It’s not just website analytics tools that can be made less effective by ad blockers. Tracking codes from other third-party sources, such as the user experience (UX) measurement tool HotJar, can also be blocked, which means that the data you get from those tools won’t reflect the full scope of visitors to your site.

As HubSpot puts it, “Marketers could lose a lot of analytical data [due to ad blockers]. Many of the most popular tools marketers use to measure and analyse visitors’ activities could be affected.”

The most obvious outcome of tracking prevention by ad blockers is that web analytics tools are caused to underestimate the volume of visitors to your website.

Further, it’s possible that untrackable visitors – those who use an ad blocker with tracking prevention activated – might behave differently, in some ways, to other visitors. For example, they may be more sensitive to features of the site which seem to compromise data privacy. So, not only do ad blockers restrict online measurement; they may also distort it.

With all that said, ad blockers are just one of many obstacles facing third-party tools like Google Analytics. Some users will prevent these tools from tracking them by declining performance tracking in a website’s cookies consent options. Others use dedicated tracking blocker applications.



Another way ad blockers can affect marketing data is blocking certain features that marketers may want to measure – such as embedded videos – on the basis that they appear to be ads, even though the features could be something else entirely.

Ad blockers generally work by detecting features in a webpage’s source code which appear to be ad-related. As a result, they sometimes block features which are described in the code with ad-related language, even if those features are not actually ads. You can avoid this potential pitfall by checking your source code for words relating to ads, and adjusting the language used where necessary.

Just as ad blockers can detect ad scripts running on a webpage, a website can be equipped to detect when an ad blocker is running on a user’s web browser. Ways to do this include implementing a “bait script” on the site with JavaScript or using a service such as Pushup. Measuring ad blocker use can help you to assess how greatly your website data is being affected by ad blocker users.


Two ways to combat ad blockers


For most brands, ad blockers are nothing worse than a minor hindrance. But for websites that rely heavily on advertising revenue, the technology poses an existential threat. Growth in the use of ad blockers has forced some sites to implement anti-adblock tactics to discourage or block the use of the technology by their visitors.

Anti-adblock tactics can be roughly split up into two categories:

  • Hard / Block
  • Gated / Nag

In a hard/block approach, the website prevents visitors from viewing content while they are using an ad blocker. When the site detects an ad blocker, a message is shown to the user explaining that they must deactivate the ad blocker or whitelist the page/domain in their ad blocker settings, or else they won’t be able to view the content. Often, the message explains how the visitor can take the required actions.

Meanwhile, in a gated/nag approach, the visitor is usually served a message which explains why ads are important to the website, and which politely asks the visitor to disable their ad blocker or whitelist the site. Sometimes, the message offers an alternative option of paying to subscribe to an ad-free version of the site.

Anti-adblock tactics can be very effective at reducing the percentage of a website’s visitors who use an ad blocker while on that site. However, anti-adblocker measures may also cause some users to abandon their attempt to visit the website. For this reason, anti-adblock tactics are best suited to businesses which rely heavily on ad revenue and user data, such as digital publishers.

Another way to reduce the impact of ad blockers is to migrate your content onto a proprietary app. While an ad blocker might be able to prevent ads from showing up on your website, it can’t do the same on an app that you own and control. You can test this theory by watching YouTube videos in your web browser with an ad blocker activated, and then watching videos on the YouTube app.


Why ad blockers aren’t exclusively bad news for marketers


So far, we’ve talked about lots of ways ad blockers can make life harder for marketers. But, looking on the bright side, there are also a few positives to receiving visits from people using these tools:

Ad blockers may speed up page loading times. In some cases, ad blockers can identify and block ads before a page loads. So, when someone using an ad blocker visits a site, they get a faster loading time, because the web browser doesn’t need to spend time loading the blocked content. This lowers the probability that these users will navigate away from the site prematurely due to slow loading.

A suitable experience for every visitor. Whereas some people hate ads, others don’t mind them, and a few might actually like them! With this in mind, the widespread use of ad blockers could be quite liberating for marketers: you can advertise on your site with confidence, because many of the visitors who dislike ads will be using an ad blocker anyway.


Could ad blockers become less impactful from 2023?


It has been suggested that ad blocking extensions will work much less effectively with the Chrome browser from 2023.

The ad blocker extensions currently available for Chrome are based on a specification which is soon to be replaced. In 2023, when Chrome rolls out a new specification for browser extensions, some of the capabilities of an important API used by many ad blockers – chrome.webRequest – will be deprecated.

According to Statcounter (checked in May 2022), Chrome has a market share of about 65% across all device types – which puts it well ahead of rival browsers Safari (19%), Edge (4%) and Firefox (a little over 3%).

Any new obstacle to ad blocking on Chrome could be highly impactful. However, this raises the question of whether a significant share of ad blocker users would switch browser, rather than making do without the ad blocking functionalities they have grown used to.

Chrome’s new specification will almost certainly prevent some visitors from using ad blockers in some of the ways they currently use them. However, the clear demand for ad blocking tech will provide ad blocking services with ample incentive to invent new workarounds. This is a game of cat-and-mouse between companies that make money from ads, and companies that make money from people who don’t want to see ads. It’s probably best to assume that the ad blocker situation will remain fluid, rather than swinging definitively to one extreme or the other.




Among the visitors to our website, there will be many people who use ad blockers, and many who don’t. Based on current average usage rates, it could be close to a 50/50 split.

We’re not saying that dealing with ad blockers should be top of your agenda – but their prevalence means it’s prudent to consider ad blockers when making decisions about your online marketing.

This is especially true for businesses that rely heavily on online ad revenue, such as digital media companies. If your business depends on advertising, you’ll need to make a plan on how to counter ad blocker use, and/or make up for the loss of ad revenue caused by ad blocking.

Even if ads aren’t especially important to your site, visitors’ use of ad blockers could still hurt your ability to track visitors with tools like Google Analytics and HotJar. With this in mind, you should be accounting for the fact that ad blockers are likely making some of your visitors untrackable.

And on another note, it’s a good idea to test how your website works for people using ad blockers. Sometimes, ad blockers prevent websites from working as they should – including components of the site that have nothing to do with advertising.

Despite their understandable appeal to web users, ad blockers are at best a nuisance, and at worst a real risk for marketers. Factoring these applications into your marketing strategy will help you to block the blockers’ worst effects.

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