Understanding how SEO works first requires that you understand how Google Search works. Many concerns and unanswered questions could be avoided. In this article, I want to explain to you how the Google search engine works. My intention is that by the end of your reading, you will be better able to understand the movements of your website pages and why some of you are not well ranked on search engines.
How does Google Search work? The Google search engine relies on crawling software, also known as crawlers, web spiders, bots, or spiders. These robots are tasked with exploring the web by following the HTML links found on website pages. This automated exploration of URLs by the search engine allows it to identify those that are relevant to be included in its index.
To schematize the functioning of Google Search, we can describe it in 3 key steps which are:
- Web page crawling from HTML links
- Indexing of URLs that meet the search engine’s interest
- Processing and ranking of these URLs according to the search engine’s relevance criteria.
Now let’s take a closer look at what these 3 steps consist of.
Understanding the crawling of web pages by search engine robots like Google means understanding that a page, once it is published, is like thrown into a limitless space. It has no label, no marker to define it.
It is precisely the role of the search engine to be continuously searching for web pages that have just been created. This step is called « URL detection ». Once a new page is detected, Google adds it to its index of known URLs.
Google detects new URLs by following the links that are integrated within web pages or from a list of URLs integrated into the sitemap.
Google, like any other search engine, has its own crawling program called Googlebot. This program uses a crawling process based on algorithms to determine which sites to crawl, how often to crawl, and the number of pages to extract from each site.
Google’s robots are also programmed to avoid crawling them too quickly in order not to overload them. This mechanism relies on site responses (for example, HTTP 500 errors mean « slow ») and on settings in the Search Console.
Googlebot may also not be able to crawl one or more pages. Google’s bot is often stopped in its tracks because a page has been banned from crawling by a site owner. Technical problems with a page can also lead Googlebot to fail to crawl the page.
Web page indexing
As soon as the search engine comes across a new page it doesn’t know, it will try to figure out its subject. This step is called indexing. The search engine’s indexing includes processing the textual content and its analysis but also processing and analysis of HTML attributes such as title tags, meta descriptions, image attributes, videos, in short, all content elements that form the page.
At the same time, the search engine will try to understand if this page it is analyzing is unique or if there is another copy somewhere else on the web from the canonical URL.
The canonical page is the page that can be displayed among the search results. Google starts by grouping (it creates a cluster) the pages found on the Internet that offer content similar to the analyzed page. It will then select the most representative page of the group.
The other pages in the group are alternative versions that can be broadcast in different contexts, for example, if the user is searching from a mobile device or searching for a very specific page from this cluster.
The information collected about the canonical page and its cluster can be stored in the Google index. Indexing is not guaranteed. Not all pages that Google processes are indexed.
Processing and ranking of web pages
As soon as a user types a search phrase, the search engine will search for all the pages available in its index that are linked. It will then send the results it has deemed most qualitative to respond to the user’s search expression.
This relevance is qualified based on more than 200 factors including the geographical area or the language of the query.
The display options in the search results that appear on the search results page also change depending on the user’s search expression.
You now know that the Google search process is a three-step mechanism, and not every page on the web always successfully makes it through all of these steps.
The first step, crawling, is when Google extracts textual, visual, and video data from pages detected on the Internet using automated programs called crawl bots.
Then, during the indexing phase, Google scrutinizes the text, images, and videos on the page, before storing this information in the Google index, a huge data directory.
The final step in the process is to provide information that closely matches its query. This is the distribution of search results.