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A Guide to Core Web Vitals and Ads in 2022

Core Web Vitals (CWV) are a key component to winning in Google Search. Knowing how to maintain and even improve your CWV is crucial for any modern website. That’s why Google provides handy tools to help you understand how your site is performing, according to their standards.

One aspect of a site that can quickly cause lots of problems with CWV is display advertising. From losing page speed to causing very bad layout shifts, advertisements are a prominent driver of poor user experiences.


Cumulative Layout Shift (CLS), in particular, can be handled in a very elegant way to ensure that the page doesn’t jump. You’ve seen it in action. You load a page on your device, start scrolling down to read the article, and then the page jumps all over the place! You then have to scroll up (or down) and try to find where you were in the article. It’s a very frustrating experience from a user’s standpoint for sure.

What often causes these jumps is a banner ad above the headline or lead media image of an article (or a tweet!). These ads come in various different pixel sizes (typically 728x90, 970x90, or 970x250) and that’s what causes the issue. Because ads are dynamically served, your browser doesn’t know what size the ad will be for any particular load. So, if the ad doesn’t load completely before you begin to scroll, you will be pushed down in your browser view when it does load, causing CLS.

This can be solved in a few different ways, one of which we consider ideal. Our preferred solution is to have a placeholder in the size of the largest ad in your stack (typically 250 px high) so that the space is already taken up by the placeholder. Then, when the ad loads, it fills in the placeholder space, assuring that no CLS occurs. To make this as aesthetically appealing as possible, we recommend vertically centering the smaller ads in the placeholder spot. This will result in white space (or you can do an attractive background color) around the shorter ads, but the benefit in reducing CLS more than makes up for the drawback.

You can see in the following example that the ad is taking up the full space (970x250):

While in this next example, we are maintaining the same placeholder height, but the ad is smaller:

This is a great way to eliminate CLS penalties, because the size of the ad doesn’t matter — we’re holding the same amount of space in each instance.

Other options that are rarely plausible or possible, are only serving tall ads, or only serving short ads. This is typically not reasonable because you will lose a good portion of the ads in your catalog and will end up not having enough to serve your traffic. This will result in a loss of revenue and is clearly not considered a good path forward.

Using strategies such as this is one of the reasons that RebelMouse leads the way in CWV and performance. We also have tools that can help you to identify where you are having problems with your CLS or other measures.

Not already publishing on RebelMouse? Get in touch with us today, and discover how we can help improve your site’s Core Web Vitals.

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Rebel Insights

RebelMouse Q1 2021 Platform Updates

Speed, performance, and Core Web Vitals enhancements

Click here to read our Q2 2021 platform performance updates!

At RebelMouse, we pour our souls into making sure that our platform is always the most modern, high-performance CMS on the market. In fact, we invested over $100,000 worth of hours into our platform in Q1 2021 alone. This has resulted in updates and performance enhancements that publishers would have to pay for on their own to make happen on any other platform, such as WordPress. We're proud to be at a level of scale where we can invest this way into our platform, and we will continue to invest at this rate every quarter moving forward just as we have in the past.

Here are the major updates that we've added to the platform in Q1.

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Google Launches Long Tap to Preview Function for Discover
Rebel Insights

Google Launches Long Tap to Preview Function for Discover

Google Discover just got a bit more interactive. SEO consultant Glenn Gabe posted on Twitter that he noticed a long tap to preview function pop up on Google Discover for Chrome users.

The new preview feature is another great reason to start optimizing your content for Google Discover. As a reminder, according to Google, Discover is a hyper-personalized feed that "actively tunes itself to a user's interests and displays content that aligns with those interests." Since Discover's feed is curated by a user's previous web activity, it's a great opportunity to expose your content to an ultra-targeted audience.

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RebelMouse Q1 2022 Platform Performance Updates
Rebel Insights

RebelMouse Q1 2022 Platform Performance Updates

Click here to read our Q4 2021 platform performance updates.

Click here to read our Q3 2021 platform performance updates.

Click here to read our Q2 2021 platform performance updates.

Click here to read our Q1 2021 platform performance updates.

RebelMouse started 2022 off strong with a continued commitment to site performance, particularly Google’s Core Web Vitals, that makes the sites within our network the fastest on the open web. In fact, our commitment to high performance was recognized by Google. We analyzed the audience behavior of a number of sites we power, both before and after we optimized for high performance scores on Core Web Vitals. On every site we analyzed, there was a significant boost in loyalty and engagement metrics. Click here to read the full case study on Google’s web.dev blog.

Here’s a bit more of what we’ve been up to since the start of the year:

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