SEO – How Search Engines Work

To do SEO well, you must know what a search engine does with your website. The work has three steps: crawl, index and rank.

Step 1: Crawling

Search engines use programs called crawlers (or bots, or spiders). Google’s crawler is named Googlebot. A crawler opens a page, reads it, and follows the links on it to find more pages. This way it moves from page to page.

  • Pages with no links pointing to them are hard to find. Link your pages from other pages.
  • You can give the crawler a list of pages with an XML sitemap.
  • You can ask crawlers not to visit some parts of the site with robots.txt.

Step 2: Indexing

After crawling, the search engine tries to understand the page: the text, the title, the images, the language and the topic. Then it saves the page in its index. A page which is not in the index cannot appear in the search results.

Not every crawled page gets indexed. Google can skip pages which are duplicate, very thin or blocked with a noindex tag. You can check the status of a page in Google Search Console.

Step 3: Ranking

When a person searches, the engine looks in its index and puts the most useful pages first. It uses many signals, for example how well the page matches the search, the quality of the content, the links from other sites, the speed, whether the page works on mobile, and the location of the user. Nobody outside Google knows the full list, and it changes often.

What you see in the results

The result page is not only ten blue links now. Depending on the search, you can see ads, featured answers, images, videos, maps, shopping boxes and AI generated summaries. Good SEO is still the way to be one of the pages which these features pick from.

Check if your page is in Google

The easy way is to search for your page address with the site: word:

site:tutorialsclass.com
site:tutorialsclass.com/seo-introduction/

This gives only a rough idea. For exact information, use the URL Inspection tool of Google Search Console.

How to help each step

StepProblemWhat to do
CrawlingGoogle cannot reach the pageAdd internal links, fix server errors, do not block it in robots.txt
IndexingGoogle reaches it but does not save itMake the content useful and unique, remove accidental noindex, use canonical tags properly
RankingThe page is indexed but low in resultsMatch the search intent, improve content, speed and links

One more thing: Google can run JavaScript, but it needs more time and resources for it. Important text and links should be in the HTML which the server sends, when possible.

Note: If a page is not found in search at all, start from the first step and ask: can the bot reach it, is it allowed to be indexed, and is it worth to be shown? Next: Types of SEO.

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