If you’re advertising online or in advertising-funded publishing, you need to know about ad blocking. In either case, this technology will potentially reduce the number of times advertising is seen, either making your campaign less effective or reducing your advertising income.

This blog post provides a primer that explains the technology and how publishers are fighting back against ad blocking. When you’ve read this, you’ll have a good understanding of the technology and the issues surrounding ad blocking.

What is Ad Blocking?

Ad blocking is a technique that removes adverts from a web page. It’s that simple, and people have developed other similar applications, including several that replace images. One example is a Chrome extension that replaces all images on a page with photos of Chuck Norris.

Why do People Block Ads?

There are a couple of reasons why people choose to block adverts: either they “don’t like ads” or they are frustrated with the time to render advertising-heavy websites. There is a huge moral debate about whether it’s ethical to access content that’s advertising funded with an ad blocker, and many publishers deploy anti ad block technology to prevent it.

Some people dislike ads because they don’t like being tracked, although ad blockers don’t necessarily block all tracking, only the adverts that are the result of tracking.

Why are Publishers so Upset?

Ad blocking is a serious threat to many publishers’ business models, particularly in B2B. Traditionally B2B magazines were typically funded by advertising, with companies keen to pay to use them to get their messages over as they knew who was receiving the magazine. This “controlled circulation” approach meant that B2B magazines were incredibly effective at getting adverts in front of the people that the advertisers wanted to reach (provided that the readers opened and read the magazine).

Today many B2B publications work on the same principle, with the audience defined by the content. The logic is that content talking about interrupt models of a microcontroller is likely to attract engineers designing with those products. Generating the level of content that is going to attract engineers, however, is difficult and requires skilled and knowledgeable journalists. And, of course, these journalists cost money.

So the position of publishers is pretty clear: although they don’t like to say this in public, they often view ad blocking as a form of stealing content, as the work of the journalists is being taken by people who are not paying because they don’t see the adverts.

Why Does My Ad Blocker Still Show Adverts?

Many ad blocking products participate in the Acceptable Ads programme, which defines guidelines as to what adverts should be shown. Some ad blockers will give you the option to enable or disable acceptable adverts.

The Acceptable Ads programme is not without controversy. Started by AdBlock Plus, the programme enables anyone whose adverts meet the criteria for acceptability to be whitelisted, but does charge the biggest advertisers for participation. Large advertisers (defined as companies that would receive 10 million impressions or more by whitelisting) are charged and pay 30% of the revenue they realise through whitelisting.

How Does an Ad Blocker Recognise an Advert?

The technology can have several ways to recognise an advert, which are referred to as filter rules. One of the most popular lists of filters is EasyList, which holds a large list of strings of text (for example “&trackingserver=”). If the ad blocker sees the string of text, then the code that includes the text is not executed, preventing adverts being displayed as well as website tracking.

Note that EasyList doesn’t stop all tracking, although the organisation does have a database of text that indicates tracking that ad blockers can used, called EasyPrivacy. There is the EasyList Cookie List that blocks all cookie banners, including the GDPR notifications that no website owner wants on their site but are forced to include because of European law.

A more comprehensive guide to ad blocking techniques is giving in the Wikipedia Ad blocking article.

How Does the Ad Blocker Stop the Advert from being Displayed?

To block the advert, the blocker simply changes the code used for the website. Normally a web page is displayed by your browser simply running through the code. Ad blockers are browser extensions, which lets them change the code before it is processed by the browser, meaning that they can detect and remove adverts and other content.

Perhaps the simplest example of how the code is changed is some websites use data:image/png; (an HTML function that doesn’t result in an HTML call that can be blocked). Ad blockers, however, simply add some CSS code that hides anything on the page displayed using this technique. Obviously, this can block elements that are not adverts, but ad blocking technology isn’t very subtle.

Dealing with Ad Blocking

There is an arms race between users and publishers over ad blocking. Realistically publishers have a limited number of options:

  • They can simply accept ad blocking and the related fall in revenue. For some B2B publishers this might be the best strategy because many companies will not allow users to deploy their own software (including ad blocking) on their PCs.
  • Publishers can use the ad networks that are whitelisted by the ad blockers. Although most systems allow users to ignore the Acceptable Ads, frequently users are happy to allow them and therefore this is one solution. Obviously, there is the tax on the large ad networks to participate in Acceptable ads that will inevitably be passed on to the publisher.
  • They can beg. Some publications ask people to whitelist the site, so they see adverts from that site. We’re not aware of any studies that show how effective this is, but we suspect that in the majority of cases the pleas to visitors’ better natures will be ignored.
  • Bypassing ad blockers is possible, but it will be a game of whack-a-mole. Finding ways to confuse the blocking software, making it display the adverts is difficult and any techniques are likely to be soon detected and patched, so successes will be short lived.
  • Publishers can refuse to allow visitors with ad blockers turned on to access their content. This seems to be a common trend today.
  • Publishers can make their sites subscription-only, without any adverts. This presents a challenge as it is hard to get people to pay money for online content, although some newspapers have done this successfully and I suspect there will be some high-quality publications that take this approach.

Personally, I like publishers who are confident enough to say that their content is valuable. If visitors are going to block ads and therefore not pay for the content. I think it’s a positive move to stop them browsing the site. Although this approach won’t make friends with the ad blocking community, it doesn’t involve any loss of revenue (the ad blocking visitors would not generate revenue anyway) and gets the message across that people who access news sites should do something to pay for the journalists that create them.

One extension of this option is to offer ad-free versions of the site if you pay a subscription. There have been a few experiments around this approach, where you can choose to see adverts or simply pay money, but it doesn’t seem to have taken off strongly in B2B technology.

Detecting Ad Blockers

Typically, when a publisher detects the use of an ad blocker, they will either display a plea to turn it off, or simply block access to the content. Detecting that a website visitor has ad blocking can be tricky: remember that ad blockers work after the HTML code for the page has been downloaded by the browser, so the website doesn’t see any of the changes being made. There are, however, some rather clever approaches that have been taken.

One simple approach is using bait. For example, a publisher might place some code inside a file called ads.js, and then try to load it from the web page. It’s pretty clear that as ad blockers use text strings, they are very likely to block the loading of any file called ads.js! So, with the loading of the file blocked, the element included in the file is not added to the page.

The clever part, however, is that the publisher can place JavaScript code on their website that detects whether the elements saved in the ads.js file are actually on the page. If they are not, then clearly the visitor is using an ad blocker, and this code can trigger an action that blocks the content and instead displays a message.

There are a range of different solutions using the bait approach, including one that was developed by the IAB and is available as open-source code to publishers.

A relatively new technology is called ad reinsertion. The battle between publishers and ad blockers has now got to the point that publishers look to detect where an ad has been removed (which will typically create a blank space) and then they insert the ad from a server that is not going to be blocked. This uses JavaScript code that contains the page’s HTML. Some ad blockers are even offering deals where publishers can pay to enable the ad to be reinserted.

There are two approaches to ad reinsertion: ad recovery puts the original advert in the empty space while ad replacement puts another advert into the space. Many organisations, however, question whether ad reinsertion is the right way for publishers to deal with ad blocking.

A third approach to dealing with ad blockers is the use of native ads: what older marketers would call “advertorials”. This simply means placing the promotion of the product or service inside an article. Native ads have been controversial as many publishers have not been completely open about when content is editorial, and when the publication is paid to carry it. It does, however, represent a way to deliver paid-for content that is not an advert as such and therefore won’t be blocked.

The Future of Online Advertising

I’d love to say that we have all the answers to the future of online advertising, but the reality is that no one really knows what will happen. In B2B marketing, however, there are a number of factors at play:

The cost of adverts in publications is very high compared with other platforms (e.g. search engine marketing or social media advertising). This suggests that there is real value in advertising in an online publication and therefore there will always be demand as it works. Publishers are also becoming more creative in how they generate money online, adding newsletters, email rental, webinars, lead generation programmes and other campaigns to their media packs.

Internet users and publishers will continue to battle in the ad blocking wars. Whether you side with users who say that the amount of advertising deployed is unacceptable and therefore ad blocking is justified, or the publishers who think that ad blockers steal their revenue, it’s likely that leadership in the arms race will swing from one side to another with no long-term winner.

Suppliers are moving towards more self-publishing, whether that is on a website, through marketing automation or with separate microsites, eBooks and other content. Customers value the technical competence of the authors of this content, but equally understand it has inherent bias and are much less trusting of self-published content than independent publications.

The large players in the online advertising market, particularly Google and Facebook will continue to try to monopolise the market. Although we frequently see stats saying that they are hoovering up most or all of the new money being spent online each year, it’s also clear that the money spent on display advertising with B2B publications is, in general, holding its own.

In the long term, I think we will end up with an equilibrium. There will be internet users who insist on using ad blockers, but equally many people will recognise the need to pay the journalists whose articles they love reading. I suspect we might see the less technically competent publications struggle to keep pace, but I’m pretty sure we will end up with a few subscription-based publications and a majority of online titles that are primarily advertising-funded. I certainly hope the advertising publications will continue: whatever your views on advertising, having high-quality content available to all engineers without the need for a cash payment has to be a good way to improve the knowledge and expertise of the engineering community.