With the rise of ad and content blockers (think Ghostery and uBlock Origin), as well as browser tracking protections (see www.cookiestatus.com), marketing technology vendors have their work cut out for them. And when I refer to “their work”, I mean they have to proactively identify and exploit any loopholes they can find to keep on collecting their precious data. In this article, I’ll take a look at one such exploit vector, the Canonical Name (CNAME) DNS record, in particular.

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Since updating to Google Chrome 83, you might have noticed that Google Tag Manager’s Preview mode no longer works when browsing Chrome in Incognito mode. This is because starting with Chrome 83, third-party cookies are blocked by default in Incognito windows. Google Tag Manager uses third-party cookies to serve browsers in Preview mode with the container draft rather than the live container. There’s a simple workaround to make sure Preview mode continues working for any site you want to browse in Preview mode.

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Let me start by proclaiming with clarity and sincerity: No, Safari 14 (or any other version of Safari) will not block Google Analytics from loading and running on a website. In the midst of Apple’s yearly Worldwide Developers Conference, the company showcased some of the privacy improvements to the upcoming version of the Safari web browser (version 14). In fact, the biggest revelation was the new Privacy Report, which is designed to elucidate how much the browser is working towards mitigating the damage caused by cross-site trackers.

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On New Year’s Eve 2018, I published an article which instructed how to scrape pages of a site and write the results into Google BigQuery. I considered it to be a cool way to build your own web scraper, as it utilized the power and scale of the Google Cloud platform combined with the flexibility of a headless crawler built on top of Puppeteer. In today’s article, I’m revisiting this solution in order to share with you its latest version, which includes a feature that you might find extremely useful when auditing the cookies that are dropped on your site.

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Recently I published an article on how to set up an impact test for the “flicker effect” omnipresent in client-side A/B-testing tools. Be sure to check out that article first to get some context to what we’re going to be talking about here. In this short follow-up, I’ll show you how to measure the average time of the anti-flicker snippet delaying page visibility, if you choose to deploy the snippet.

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“Flickering” or “Flash Of Original Content” (FOOC) is a phenomenon where there’s a (typically) slight but observable delay in the browser updating the site or element layout if the user is included in a variant group for experimentation. This manifests in the original, unmodified element being rendered in the visible portion of the page before the experiment library updates it with the variant. There are ways to mitigate the flicker:

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When custom templates were released for Google Tag Manager, I updated my workflow for working with GTM. Instead of instinctively rushing to the Custom HTML tag and the Custom JavaScript variable, I started considering whether the custom script that needed to be deployed could be transformed into a custom template first. While publishing numerous templates into the community gallery, I always spent some time over the past 12 months tinkering on an extremely complicated template translation: the Snowplow Analytics JavaScript tracker.

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