In December, Google rolled out its fourth and final core update of 2024 alongside a spam update. The core update aimed to refine ranking factors, impacting many websites across different sectors. Simultaneously, the spam update focused on combating spammy content and web practices, improving the overall search experience.
Along with these updates, a recent episode of the Google Search Off The Record podcast issued a warning regarding the overuse of JavaScript on websites and its effect on crawler rendering, particularly in the advent and rise of AI search crawlers.
Finally, in other news, Google has formalised guidelines for faceted navigation, a key element in organising and delivering large amounts of content on websites. Building on a previous blog post from 2024, they have translated this into official technical documentation which provides users with clear implementation options and updated recommendations. We’ll explore this alongside the other updates in more detail below.
Allow our traffic light system to guide you to the articles that need your attention, so watch out for Red light updates as they’re major changes that will need you to take action, whereas amber updates may make you think and are definitely worth knowing but aren’t urgent. And finally, green light updates which are great for your SEO and site knowledge but are less significant than others
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In this post, we’ll explore:
The December 2024 core update launched on the 12th of December and concluded on the 18th of December, spanning six days and marking it as the fastest documented, official core update in Google’s history.
As with most updates, Google was hesitant to release many details about this update, however, they did state, “If you’re wondering why there’s a core update this month after one last month, we have different core systems we’re always improving.” leading many to speculate that this one focused on something different compared to the last.
Despite its quick rollout, the update brought lots of volatility with many data providers citing it as more volatile than the November 2024 core update. Data from Semrush suggested that there was an average position gain/loss of around 2.8 positions from this update compared to 2.4 for November.
Volatility began to spike around the 13th and 14th of December, continuing this trend throughout its rollout.

However, further findings from SimilarWeb showed that the update was less volatile than the March and August core updates.

Images taken from Search Engine Land
However, further takeaways suggest that this update had a positive impact on sites that were negatively affected by the previous core update just a couple of weeks before. Delving deeper into specific industries, the analysis suggested that the finance niche experienced lower levels of fluctuations in the top 3 results whereas the health niche showed comparable levels of SERP fluctuations in both the top 3 and top 5 search results.
While December 2024’s updates affected some websites negatively, the overall reaction was more positive compared to previous ones, perhaps marking a shift toward a more forgiving stance on sites impacted previously.
Explore our comprehensive guide to read more about all the Google algorithm updates to date.
The Google December 2024 Spam Update rolled out from the 19th of December to the 26th of December. It is the third spam update of the year and came just a day after the December 2024 Core Update. It was a broad spam update, not focused on link spam or automating site reputation abuse policies, which still require manual actions.
While its exact targets are unclear, together with the Core Update, sites may have witnessed higher volatility and ranking fluctuations. Analysis suggests that holiday traffic fluctuations may distort visibility, so it is better to focus on rankings rather than traffic to assess the effects.
Sites affected by spam updates should review Google’s spam policies and make necessary changes to comply. Fixes may take months to reflect in rankings, and in the case of link spam, lost ranking benefits may not be recoverable.
In a recent Google Search Off The Record podcast, the Search Relations team emphasised the challenges of integrating JavaScript effectively with modern search tools. While JavaScript has been key for allowing websites to incorporate dynamic features like push notifications and interactive maps, overusing it can be problematic.
Martin Splitt, a Search Developer Advocate at Google, explained that JavaScript was initially designed to help websites compete with mobile apps. He discussed how JavaScript is often used unnecessarily, which can negatively impact a website’s performance in search, especially with the rise of AI search crawlers that rely more heavily on HTML.
AI search crawlers, like GPTBot, are growing in importance with one study suggesting that they now account for 28% of Googlebot’s traffic, meaning that an effective JavaScript SEO strategy is more crucial than ever.
Why AI crawlers struggle with JavaScript
However, AI search crawlers struggle to render JavaScript effectively, instead relying on server-side rendering and HTML. Studies show GPTBot favours HTML, making excessive use of client-side JavaScript a risk to visibility. This highlights how server-side rendering and HTML-first strategies are essential for optimising content for AI-driven search.
How to adapt to AI-driven search trends
To ensure your website remains discoverable, there are a number of things you can do to ensure your website is both functional for users and accessible to AI search crawlers.
- Implement server-side rendering for essential content
- Embed core information such as the main content, metadata and navigation structures in the initial HTML
- Use static site generation or incremental static regeneration where possible
- Use JavaScript sparingly and with caution
By prioritising accessibility for both traditional and AI crawlers, websites can be future-proofed for sustaining online visibility whilst enhancing the user experience.
Google has released official documentation on managing faceted navigation, which was previously addressed in a 2014 blog post. Faceted navigation, commonly used on e-commerce sites for filtering products, poses SEO challenges by generating numerous URL combinations that can overload servers, waste crawl budgets, and weaken SEO performance.
The new guidance emphasises performance optimisation and provides updated recommendations to handle modern SEO practices, including single-page applications. Google suggests two approaches for e-commerce sites to balance user-friendly filtering with SEO efficiency:
- Non-Critical Filters – Block with robots.txt, use URL fragments, or apply rel=”nofollow” attributes.
- Business-Critical Filters – Standardise URL parameters, handle 404 errors properly and implement canonical tags strategically.
