By the Webtrekk Team

It has gotten pretty easy for Internet users to block analytics tools. 

As an analytics provider, that’s not easy for us to say. But it’s true.

AdBlock Plus, for example, is a browser extension that has been downloaded hundreds of millions of times for Firefox and Chrome. In addition to preventing ads from displaying, it can easily be configured to block analytics. This took about 20 seconds:

Ghostery is another extension that millions of internet users utilize to make themselves invisible to analytics tools. Ghostery identifies the trackers on any site, and lets people block them with a click.



In the US, about 15% of online audiences use ad blocking software. Here in Germany, it’s about 25%. The people using these extensions are tech-savvy and young (a demographic that most websites would love to capture).

As a result, 25% of total traffic might mean something like 50% of 18-34 year-olds. That leaves analysts and marketers stuck with sampled data that is not even reflective of their actual audience.

How are you supposed to create campaigns if you don’t know what 25% of your visitors are doing?

How can you allocate resources when a chunk of engagement and conversions is invisible?

We know how problematic this can be. That’s why we created a solution to ensure that behavior from all users – even the ones using blockers – is reflected in your analytics data.

How blockers work

Just to be clear, all data collected with Webtrekk software is anonymous. The data is also never stored by us or given to third parties. So if someone installs an extension to remain anonymous and avoid being chased around the web by advertising tools – well, they will remain anonymous and won’t be chased around the web by advertising tools.

OK, this was going to get technical at some point, so let’s go ahead and get started.

Ad blockers generally have two ways of finding and blocking ads:

1. Crawling the HTML code of a website and hiding any element that looks like an advertisement. That’s an oversimplification, but this first method is less relevant than:

2. Preventing browsers from accepting incoming “assets” that originate from certain domains, and preventing browsers from sending outgoing information to those domains.

For example, ad4mat is a well-known retargeting provider. If someone were using an ad blocker, then this asset – viewed here with simple developer tools – would be rejected.

The same logic can be applied to block analytics, not just ads: Anything coming from an analytics provider can be stopped in its tracks.

Ghostery works similarly to this second method. If a user decides to block Google Analytics, for example, then Ghostery disrupts communication between the browser and Google Analytics.

When applied to analytics tools, these extensions are like a mute button for internet users. They are also a headache for analysts who want to know what those users are doing.

Domains explained

Here is what it looks like when a website uses analytics tools. The user lands on a page, and a tiny JavaScript file – analytics.js, highlighted in blue – is downloaded by the browser. That file comes from a server that can be identified by the “Request URL”:

Once downloaded, that JavaScript file delivers information to an analytics tool.

If someone has configured an extension to block Google Analytics, then this analytics.js file will never be accepted by the browser because its origin has been blacklisted.

There is, however, a workaround. Companies can host analytics JavaScript files on their own servers, allowing those files to be delivered to browsers from inside a company’s domain.

Let’s say a company called ABCDEFG hosted its own analytics JavaScript files. Those analytics files would come from ABCDEFG’s domain

This is brilliant because legitimate files are sent from domains to browsers all the time, whether it’s The Guardian loading files from a Guardian domain…

… or Goldman Sachs loading files from a Goldman Sachs domain…

If activity from these domains were blocked, then people wouldn’t be able to surf the web. Images wouldn’t load. Recommendations wouldn’t load. Forms wouldn’t load. 

So from the browser’s point of view, analytics JavaScript files that originate from a company’s own domain look like normal communication between the domain and the browser. It looks native to the website.

Custom track domains

However! Once it lands in a browser, that JavaScript file needs to send data somewhere.

And this is where things can go wrong for marketers and analysts – even if the .js file is hosted and delivered from within a company’s own domain, and even if it has a covert file name like kujyhks#1.js instead of analytics.js.

As Ghostery explains: “If you’ve configured Ghostery to block communication with one or more of these companies, it interrupts the call from leaving the browser.”

So an analytics JavaScript file might be accepted by the browser – but it will be useless. The destination of the data is blocked.

If you’ve made it this far, then you can probably see where this is going. With Webtrekk custom track domains, your analytics JavaScript files originate from inside your own domain. And they are also sending data to… your own domain.

This way, instead of data being sent to an external domain that might be blocked, it is sent to a destination inside the domain that the user is already browsing.

A custom track domain is like a private living space that enables your analytics software to reside within your domain. This is vital because the ad blockers and Ghosteries of the world work by identifying and stifling communication between the browser and external domains.

So not only can track domains deliver JavaScript files in a way that external domains can’t, but the data going the other way – from the browser to the analytics tools – never leave the domain. And for all the reasons discussed above, blocker extensions don’t want to muddy communication between the user and the domain that they have chosen to browse.

Cat and mouse: to be continued

The Extensions v Analytics battle is a game of cat and mouse: Companies like us figure out a way to collect data, and then companies like Ghostery put up a roadblock. Then we find a way around that roadblock and then repeat.

But in the evolution of this cat and mouse game, we can now significantly reduce the collateral damage that blockers inflict on your data.

All you have to do is create a sub-domain, and we’ll handle the configuration and other heavy lifting.

In this era of missing data and easy-to-use blockers, Webtrekk track domains let our customers sponge up data on almost 100% of their visitors. Sure, we’ll eventually need to make some tweaks to combat whatever the other side comes up with next.

But in the meantime, if you don’t want to worry about ad blockers and other browser extensions messing up your analytics data, you now have an answer to the problem of invisible visitors.