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In recent years, the SEO landscape has been revolutionized by the introduction of Core Web Vitals by Google, fundamental parameters for measuring the quality of the user experience on a website. Traditionally, many sites have opted to install additional services, such as e-commerce or blogs, in subdirectories of the main domain, a choice considered advantageous for SEO. However, with i Core Web Vitals have become official ranking factors, it is time to reconsider this strategy. We'll explore how installing in subdirectories can negatively affect your site's overall SEO score and explore the option of using separate third tiers.
Core Web Vitals: What They Are and How They Work
I Core Web Vitals are a set of specific metrics defined by Google to evaluate a user's experience on a web page. These include:
- Largest Contentful Paint (LCP): Measures the time it takes to load the main content of a page. A fast loading time is indicative of a good user experience.
- First Input Delay (FID): Evaluates the time it takes for a page to become interactive. The shorter this time, the better the experience for the user.
- Cumulative Layout Shift (CLS): Quantify the visual stability of the page while loading. A stable page improves the user experience by avoiding accidental clicks.
These metrics are primarily collected via Chromium-based browsers, which send data to Google. This reporting process allows Google to understand the efficiency of a web page from the end user's perspective.
Chromium-based browsers use a mechanism called “User Experience Report” (CrUX) to collect user experience data. Core Web Vitals and send them to Google. This reporting process plays a crucial role in determining the efficiency of a web page from the end user's perspective. Below, it is illustrated in detail how the data is sent:
- Background Data Collection: As users browse the web, Chromium-based browsers collect anonymous data about the performance of the pages they visit. This data includes metrics like Largest Contentful Paint (LCP), First Input Delay (FID), and Cumulative Layout Shift (CLS), which are indicative of the user experience on each page.
- Using HTTP Beacons: To transmit this data to Google, Chromium uses “HTTP beacons”. Beacons are small network requests sent by your browser to Google's server. These requests are designed to be lightweight and non-blocking, meaning they can be sent in the background without affecting the user's browsing performance.
- Data Format and Transmission: The collected data is compacted into a format that reduces its weight, while maintaining all essential information. When the browser detects an appropriate moment, it sends the collected data to the Google server using beacon technology. This time is generally chosen to minimize the impact on browser performance, for example when the network is less congested.
- Processing and Anonymization: Once received by Google, the data is processed to ensure user anonymity. Google aggregates performance data from multiple users to avoid identifying individuals. Only after this aggregation, the data is used to analyze web page performance trends globally.
- Feedback to Developers and SEOs: Through tools like Google PageSpeed Insights and other SEO reports, Google makes analyzes based on the data collected available to web developers and SEO professionals. This allows them to identify performance issues on their pages and implement targeted improvements to optimize them Core Web Vitals.
- Impact on Ranking: Google uses this aggregate information in its algorithms to influence the ranking of pages in search results. The pages that show best Core Web Vitals they tend to have better rankings, reflecting the importance of a good user experience.
Hypothetical Case Study: WordPress Blog and WooCommerce Shop
Let's consider a purely hypothetical case of the example.it site, which hosts a blog on WordPress and decides to integrate a WooCommerce shop in the example.it/shop/ subdirectory, rather than opting for a third level, such as shop.example.it.
The choice of this configuration implies a series of technical and strategic considerations that are very relevant for the overall performance of the site and its SEO positioning.
First of all, the performance of the site: the loading speed of web pages is a fundamental element for a good user experience and for ranking on Google. If the shop section, hosted in the subdirectory, is not optimized for loading speed, it can be significantly slower than other parts of the site. This discrepancy in performance can have a direct impact on Core Web Vitals, the metrics evaluated by Google to determine the quality of the user experience. Because Google considers site performance holistically, even a single under-optimized section, such as the online store, can lower the overall site score. Core Web Vitals of the entire domain. This drop in rating can lead to a worsening of the site's ranking in search results pages.
On the other hand, the SEO implications of a similar setup are considerable. When Google analyzes a site, it considers the entire domain as a single entity and the performance of one part of the site can be reflected in the entire domain. Therefore, if a subdirectory like /shop/ exhibits high loading times or stability issues, these inefficiencies reflect negatively on the entire site. This means that while the homepage or other sections can be optimized for fast loading times and a smooth user interface, the presence of a slower section can decrease Google's perceived quality of the site, thus negatively impacting visibility. domain overall in search results.
Specifically, here are the two problems:
- Site Performance: If the shop section is less optimized and slower, it will negatively affect i Core Web Vitals of the entire domain. Google evaluates site performance holistically, which means that a slow part of the site can lower the overall SEO score.
- SEO implications: A poorer installation in a subdirectory can hurt your domain's overall visibility in search results, despite optimization efforts on the home page or other fast sections of the site.
A highly qualified professional systems engineer could make a strong case for using advanced caching technologies, such as Varnish, to significantly speed up the shop section of a site as well, making it comparable in terms of speed to the blog section. Varnish, in fact, is able to cache static web pages and serve them quickly, drastically reducing the Time to First Byte (TTFB) and improving the overall user experience. This can be extremely effective for blog pages, where the content does not change frequently and can be easily cached and served to users without requiring server processing each time.
However, it is essential to consider the inherent limitations of e-commerce and the implications of caching in this context. In critical sections of an e-commerce site, such as the login, cart and checkout pages, caching cannot be used in the same way. These pages require dynamic interaction with the user and often contain sensitive and personalized information, which varies from one user to another and from one session to another. For example, the contents of a user's cart or the details of a payment must be managed in real time, making the use of caching impractical.
In these circumstances, the responsiveness of the site depends entirely on the native speed of the application itself, without the support of caching technology. Therefore, although parts of the site such as the blog can benefit from extremely fast loading times with a TTFB of around 50 ms thanks to aggressive caching strategies, dynamic e-commerce sections will operate at a much slower speed, linked to intrinsic performance of the server and web application. This performance gap can negatively affect the overall user experience and, as a result, i Core Web Vitals of the site, with a direct impact on SEO ranking.
Additionally, these dynamic areas of e-commerce are particularly sensitive to traffic variations, which can further degrade performance during peak access, such as during promotions or special events.
Extension of the Problem to slow parts and not just e-commerce.
The problem of the negative impact on Core Web Vitals it is not limited only to the e-commerce sections of a site, but also extends to other complex and dynamic areas such as areas reserved for logged in users, membership platforms and control panels. These sections, due to their intrinsically dynamic and personalized nature, often cannot effectively benefit from caching strategies. This is because the data displayed is unique to each user and must be generated in real time, requiring constant interactions with the database and site backend.
For example, control panels (like WordPress' wp-admin for example), used frequently by site administrators, can become particularly problematic. These panels are often designed without specific optimization for speed, as priority is typically given to functionality and security. If multiple users, particularly administrators or content managers, access these areas using Chromium-based browsers, their use may be tracked and detected as part of the overall user experience of the site. As a result, if these sessions are slow and inefficient, they could send negative signals to Google, negatively impacting your Core Web Vitals and, by extension, the site's ranking.
An effective mitigation strategy for these issues could be to adopt browsers that do not participate in sending metrics Core Web Vitals to Google. For example, encourage the use of browsers such as Firefox, which currently does not contribute to data collection Core Web Vitals sent to Google, it can be a practical solution.
Using Firefox, administrators and team members can access control panels and manage site functions without their activities impacting performance as perceived and measured by Google.
This allows you to separate the often less optimized backend performance from the influence on the site's performance metrics displayed to the public and evaluated by search engines.
Conclusions and Recommendations
When a significant portion of a site's traffic is concentrated in lower-performing areas, such as an online store, isolating these services on a separate third tier becomes a very effective strategy. This approach allows you to segregate more resource-intensive or lower-performing components of the site, such as checkout or product display pages, from the rest of the site that could be optimized for speed and efficiency.
Isolating your store on a subdomain, such as shop.example.it, can offer numerous technical and SEO benefits. From a technical point of view, this separation allows you to apply specific server configurations that are optimized for the needs of e-commerce, such as customized cache management, user session optimization and transaction security. This can significantly improve the performance of e-commerce pages without impacting the performance of the main site, which can be configured in a more streamlined and faster way to optimize static content such as blog articles, informational landing pages and more.
From an SEO perspective, keeping your main site fast and responsive is crucial as it is often the first interaction a user has with your brand via organic search. A fast home site not only improves user experience, but positively impacts Core Web Vitals, factors now considered by Google for ranking in its SERPs (Search Engine Results Pages). Connecting the main site to the shop subdomain through direct links, such as promotional banners, navigation menus or specific calls-to-action, facilitates user access to the e-commerce sections without compromising the performance of the main site.
This setup helps maintain a balance between maintaining high performance for the main site and providing the necessary functionality and management capability for the e-commerce portions of the site. Furthermore, this clear and defined separation between contents allows Google to evaluate the performance of the main site regardless of the possible burdens introduced by the e-commerce functions. This ensures that any slowdown on the subdomain does not penalize the main domain, preserving its ranking and visibility.
