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How Search Engines Work

Updated: Apr 15, 2022

Search engines are created to discover, filter, and organize content across the web.

Its main goal is to put forward the most useful and relevant results to the keywords people are searching for.

If you want to appear in the search results, your content has to first gain online visibility.

Webmasters often use Search Engine Optimization to achieve that objective.

Nowadays, SEO is considered the second most important thing after content quality, because it helps increase the popularity of a website on the internet.

Furthermore, SEO is like adding equity to your brand.

It's an investment, not a cost. What you invest today stays there for the long term.

How Search Engines Work

Search engines play three important roles on the internet, namely gathering information from every URL they come across, storing the information they have collected in their database so that it can be displayed when related keywords are searched, and providing the most popular and relevant pieces of information to

answer a searcher's query.

These three processes are called crawling, indexing, and ranking, respectively.


Crawling is a search engine’s process of discovering new and updated content through the use of robots called spiders or crawlers.

These robots find various kinds of content from a webpage to an image, a video, and a document.

No matter what the type, content is found by links.

The robots crawl web pages one after another to discover new information worth indexing.

Initially, the spiders fetch some web pages and then visit the links on those pages to discover new URLs.

This scour occurs continuously as the spiders always try to find new content to include in their huge database.

The stored content will later be retrieved according to the keywords typed into the search engine.


The indexing process is when search engines select and store the content they find in a massive database called an index, which contains all of the discovered information considered good enough to show to searchers.


When search engines are operated, they use their index to return high-quality results that are sorted by relevance.

So the more relevant a piece of content is in the eyes of search engines, the higher it ranks.

There are ways to prevent crawlers from indexing part or all of a website, one of which is by using robots.txt.

Although this can be done for certain reasons, it’s always better to make sure that the website is fully indexable before instructing the spiders to skip some of its pages or even its whole content.

Can Search Engines Crawl Your Pages?

When you have a new website, you may want to check how many of its pages are indexed, because it’s important to know how much Google pays attention to your online presence.

If the search engine picks up the pages you want to be included in its library and ignores the ones that you want it to ignore, then there’s nothing to worry about.

But if your site is not displayed in search results as you wish, your SEO efforts

might need to be improved.

You can check your indexed pages by typing: "" into Google’s search bar.

This will give you results only from that specific site.

While the search engine rarely displays the exact number of results, it does give you a clear insight into which pages of your site are indexed and the way they're sorted.

To get more complete data, you can use Google Search Console and submit your sitemap to it.

The tool can provide you with more detailed index analysis results among other things.

In the worst-case scenario, if your website is totally invisible, it can be due to one or more of the following reasons:

  • Your website is still new and search engines haven’t yet discovered it.

  • Your website hasn’t gotten any external links pointing to it to boost its popularity.

  • The navigation on your website generates a non-effective crawling behavior from a robot.

  • There’s some basic code known as crawl directives in your website that is blocking search indexing.

  • Google has flagged your website for using spammy tricks.

How Do Search Engines Store Your Content?

As mentioned before, the index is where the discovered content is stored.

When a crawler hits a web page, it renders the page as a browser would.

During this process, the search engine examines that page's content, after which the whole information gained is stored in its index.

The Way URLs Are Ranked

Search engines want to make sure that internet users get the information they’re searching for by employing ranking systems that order search results of a given query by relevance.

So there are algorithms or a process by which indexed content is returned and sorted in ways that prioritize quality.

These algorithms are continuously updated over the years for one main purpose, which is to provide higher quality search results.

For instance, a search giant like Google adjusts its algorithm on a daily basis.

Most of the time it applies minor changes, but there are occasions when the company deploys major algorithm updates to deal with a particular problem, like Penguin to deal with manipulative link building.

Yes, Google makes frequent algorithm changes to keep SEO practitioners on their toes.

Of course, this causes pages to come and go in search results.

But on the positive side, people get the most relevant content they’re searching for.

If you want to better understand what Google actually wants from a website, you can read its Webmaster Quality Guidelines or Search Quality Rater Guidelines.

In The End, Not All Searches Are Created Equal

Newcomers in web development aren’t sure about the “weight” of particular search engines.

The majority of internet users, however, recognize that Google is the biggest player.

But should you also optimize for Yahoo, Bing, and others?

Well, it wouldn't hurt to do that.

But it's worth noting that Google remains the number one despite the presence of dozens of big competitors in the global search engine market.

With this truth in mind, it’s no surprise that most of the SEO community only cares about Google - because they realize that the vast majority of people explore the web through Google.

Over 90% of internet searches take place on this search engine, and that amount is far more than Yahoo and Bing combined!

I hope you found this article useful. Leave me a comment!



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