{"id":139026,"date":"2025-03-17T06:41:15","date_gmt":"2025-03-17T06:41:15","guid":{"rendered":"https:\/\/peraltafinancing.com\/analytics\/measure-ad-and-content-blocker-impact\/"},"modified":"2025-03-17T06:41:15","modified_gmt":"2025-03-17T06:41:15","slug":"measure-ad-and-content-blocker-impact","status":"publish","type":"post","link":"https:\/\/fivemor.com\/?p=139026","title":{"rendered":"Measure Ad And Content Blocker Impact"},"content":{"rendered":"


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So, looks like iOS 9 has built-in support for integrating \u201ccontent blocking<\/a>\u201d extensions on your iPhone. Now, blocking ads and other intrusive content is nothing new, nor do I want to get into a debate about whether it\u2019s a good thing or not. But as a data geek I\u2019m very interested in knowing just what share of my site tracking has some content blocker enabled. In this post, I\u2019ll show two tricks (easy and advanced) to expose these content blockers. It\u2019s always a good idea to keep tabs on the numbers, especially if you\u2019re concerned about them blocking your analytics tools as well (as you should be!).<\/p>\n

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\"Detect<\/p>\n

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The two solutions I\u2019m going to introduce differ in their accuracy. Both require that you upload a small file to your web server. After that, the accuracy depends on whether or not you\u2019re interested in knowing how many of these content blockers end up blocking Google Tag Manager<\/a> as well! As it turns out, there are some that do, and you might want to measure that traffic as well.<\/p>\n

NOTE<\/strong>! Just to dispel any confusion, the following solutions will not<\/strong> work if Google Analytics tracking is blocked by preventing the HTTP request from ever leaving the site. The hack using an XMLHttpRequest()<\/code> will circumvent those blockers which simply prevent analytics.js from loading, but it will not help if the HTTP request to Google Analytics is blocked. To measure THAT share of traffic in GA, you\u2019ll need to relay the hits via a local web server endpoint, and send the Measurement Protocol hit to Google Analytics from your web server, where ad and content blockers can\u2019t reach it.<\/p>\n


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Create the JavaScript file and upload it<\/h2>\n

First thing you need to do is create a simple JavaScript file called advertisement.js<\/code> and upload it to the web server. This file has just one single line:<\/p>\n

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window<\/span>['noBlocker'<\/span>] = true<\/span>;\n<\/code><\/pre>\n<\/div>\n
This file functions as bait<\/strong>. It has the most blatant name you could think to give to an ad library, so most of the blockers should latch onto it with their greedy, publishers\u2019-livelihood-decimating-tendrils.<\/p>\n
You need to upload this file to some location on your web server where you can link to it from your page template (or from GTM). Because I\u2019m using WordPress, I uploaded it to the directory \/wp-content\/<\/code>.<\/p>\n
Once you\u2019ve done this, you can follow either the easy solution (coming up soon), or the more intricate one (coming up later in the article). But start by reading the generic GTM configuration you\u2019ll need for either approach.<\/p>\n
Google Tag Manager configuration<\/h2>\n
First, you\u2019ll need a Custom JavaScript Variable<\/strong>, which we\u2019ll call {{JS – noBlocker}}<\/strong>. This Variable has the following code within:<\/p>\n
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function<\/span>() {\n  return<\/span> window<\/span>['noBlocker'<\/span>] ? undefined<\/span> : 'true'<\/span>;\n}\n<\/code><\/pre>\n<\/div>\n
This will return nothing if the advertisement.js<\/code> file loaded and created the global variable, and \u2018true\u2019<\/strong> if the file was not loaded. In other words, if a content blocker blocked advertisement.js<\/code>, this Variable will return \u2018true\u2019.<\/p>\n
Next, you\u2019ll need to create a Custom Dimension in Google Analytics. I\u2019ve chosen Session<\/strong> as the scope, as Hit-level might be too granular, and User-level might be too broad. But it\u2019s up to you. When you create the Custom Dimension, make note of the Index<\/strong> number that GA assigns to it.<\/p>\n
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    \"Custom<\/p>\n
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Next, edit your generic Page View<\/strong> Tag. You need to add a new Custom Dimension row to it, with the Index number derived from Google Analytics\u2019 settings, where you just created the new dimension. The value of this dimension needs to be the Custom JavaScript Variable you created earlier. So it would look like this:<\/p>\n
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    \"Custom<\/p>\n
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Let\u2019s look at what\u2019s going on here. When this Tag fires, it tries to populate Custom Dimension with Index number 4 with whatever the variable {{JS – noBlocker}}<\/strong> returns. If the site did not load the file advertisement.js<\/code>, this dimension gets the value \u2018true\u2019<\/strong>, which is what\u2019s dispatched to Google Analytics. If the file did<\/em> load, the variable returns undefined<\/code>, and the dimension does not get sent<\/a>.<\/p>\n
And that\u2019s the generic setup! That\u2019s how we\u2019ll know if a content blocker is running on the site or not.<\/p>\n
Next, we\u2019ll need to choose how to link the file to the site, and whether or not we want to account for blockers that actually block GTM as well.<\/p>\n