Search Engine Basics

Shahid Maqbool

By Shahid Maqbool
On Jul 27, 2023

Search Engine Basics

What Is A Search Engine?

A search engine is an online tool or software application that allows users to search for information on the internet.

Here is a complete guide on search engines, their types, and functions. Make sure to read it for a comprehensive understanding.

How Do Search Engines Work?

To comprehend how SEO works, it's essential to grasp the basics of search engine operations.

FYI: As of June 2023, Google owns 92.66% of the search engine market. This means that more than 9 out of every 10 search queries are conducted on Google. The next two most popular search engines, Bing and Yahoo!, have market shares of 2.76% and 1.09%, respectively. Since Google is the most popular search engine, we will mainly discuss its operations and processes.


Search engines like Google utilize crawlers or bots, which are programs designed to discover new pages on the web. This process is known as crawling.

The crawlers continuously browse the internet to find and gather information from various websites.

"URL discovery" is the first stage where Google seeks to find out what web pages exist on the internet. 

Unlike a centralized registry of all web pages, Google continuously looks for new and updated pages by various means.

Some pages are already known to Google because its crawlers have previously visited them. Other pages are discovered when Google's crawlers follow links from known pages to new ones.

For example, a blog post may link to a newly published or relevant blog post. Additionally, webmasters can submit a list of pages, known as a sitemap, to Google for crawling.

After discovering a page's URL, Googlebot may visit the page to gather information about its content. Google employs a vast array of computers to crawl billions of web pages.

The crawling process is based on an algorithmic process that determines which sites to crawl, how often to do it, and how many pages to fetch from each site.

Google's crawlers are programmed to avoid overloading websites, and they adjust the crawl speed based on the responses from the site and settings in Search Console.

However, it's essential to note that not all discovered pages are crawled. There are certain scenarios in which Googlebot may not crawl a page.

For instance, site owners can disallow the crawling of specific pages using rules in the "robots.txt" file. Additionally, some pages may require users to log in to access the content, making them inaccessible to crawlers.

During the crawling process, Google renders the page, meaning it loads the page and executes any JavaScript code present on it. This rendering process is crucial because many websites rely on JavaScript to display their content.

Without rendering, Google might not be able to see the full content and structure of the page accurately.

Several factors can affect Googlebot's ability to access and crawl a site, leading to crawling issues.

Common issues include problems with the server handling the site, network connectivity issues, or specific rules set in the site's "robots.txt" file that prevent Googlebot's access to certain pages.


After Google's crawlers have visited and fetched a web page, the next step is indexing, where Google aims to understand the page's content and meaning.

This process involves analyzing the textual content and various key content tags and attributes, such as the title element (<title>) and alt attributes for images and videos.

During indexing, Google also checks whether the page is a duplicate of another page already present on the internet. If duplicates are found, Google identifies a canonical page, which is the most representative page among the duplicates.

The canonical page is the one that may appear in search results. The other pages with similar content are considered alternate versions and might be served in specific contexts, such as for mobile users or users seeking very specific information from that group.

To determine the canonical page, Google first clusters together the pages with similar content. From that cluster, the most representative page is selected as the canonical.

This process helps Google avoid showing duplicate content in search results and provide users with the most relevant and diverse information.

During indexing, Google collects various signals related to the canonical page and its content. These signals include the language of the page, the country where the content is relevant or localized, and the usability of the page.

These signals play a role in the subsequent stage, where Google decides which pages to show in search results for specific user queries.

The information gathered about the canonical page and its cluster is stored in the Google index. The Google index is a vast database hosted on thousands of computers that contains information about the web pages Google has crawled.

However, it's essential to note that not every page Google processes will be indexed. Some pages may not meet the criteria for indexing or may have issues that prevent proper indexing.

Several common issues can affect indexing. For instance, pages with low-quality content may not be indexed because Google aims to provide high-quality and relevant results to users.

Additionally, if a page has a "robots meta" tag with instructions disallowing indexing, Google will respect those directives and exclude the page from the index.

Moreover, certain website designs might present challenges for proper indexing, leading to indexing difficulties for those pages.

Ranking & Serving Search Results

Finally, when users perform a search query, the search engine employs complex algorithms to sift through the index and determine the best and most relevant pages that match the search intent.

These algorithms consider various factors, such as keyword relevance, content quality, backlinks, user experience, and many others.

The search engine then presents the selected pages as ordered search results, with the most relevant and authoritative pages ranking higher on the results page. 

This process of selecting and presenting search results is known as ranking.

Keep in mind, search engines have hundreds of factors that go into both indexing and ranking.

Furthermore, they constantly update their algorithms, aiming to improve the quality of search results for users. They may also personalise search results based on a user's previous behaviour.

Google's Search Console is a tool that website owners can use to monitor their site's performance in Google search results.

Sometimes, webmasters may notice that a page is indexed in the Google index (as indicated by Search Console), but it doesn't appear in the search results.

There can be multiple reasons for that:

Irrelevant Content

Google's algorithms strive to provide users with content that matches their intentions, and if a page's content is not deemed relevant, it may not be shown in the search results.

Low-Quality Content

If the content on the page is of low quality, lacks credibility, or is poorly written, Google is less likely to display it in the search results. High-quality, informative content is given preference in search rankings.

Robots Meta Rules

Website owners can use the “robots meta tag” to instruct search engines on how to handle their web pages.

If a page's robots meta rules prevent it from being indexed or displayed in search results, Google will adhere to those directives.

What Else You Need To Know?

Google Search Essentials (formerly known as Google Webmaster Guidelines) is a set of guidelines and best practices that assist webmasters in creating and optimizing their websites for Google Search.

These essentials encompass various topics, such as technical requirements, spam policies, and creating valuable, reliable content.

Adhering to these guidelines is crucial for website owners, as it can significantly impact a website's performance in search results and ensure a positive user experience.

Google provides these guidelines to help webmasters understand how the search engine works and what practices to follow for better visibility and compliance with search engine standards.

Similarly, other search engines like Bing also have their own guidelines that website owners should consider for effective optimization.

How Do Search Engines Personalize Results?

Search engines, like Google, employ personalization techniques to tailor search results for each user based on various factors.

These personalized search results aim to provide users with more relevant and localized information, enhancing their search experience.

Here's how search engines personalize the results:


Search engines, especially Google, use the user's location data to deliver search results with local intent.

For instance, when someone searches for "Turkish restaurant," Google will display results from or about local Turkish restaurants in the user's vicinity.

This is because Google understands that users are more likely to be interested in nearby options rather than distant ones.


To cater to users speaking different languages, search engines prioritize displaying search results in the user's preferred language.

For example, if a user's browser or device settings indicate German as their language preference, Google will prioritize showing search results in German or prioritize localized versions of content available in German.

Search History

Search engines, like Google, save users' search history and behaviour to better understand their interests and preferences. This accumulated data helps in delivering more personalized search results over time.

For example, if a user often searches for topics related to photography, Google may prioritize photography-related content in their future search results to enhance relevancy.

While this personalization can be beneficial as it delivers more relevant information to users, it's essential to be mindful of data privacy and opt-out options provided by search engines for users who wish to limit data collection for personalization purposes.

Key Takeaways

  • Google's crawlers find pages through various means, including following links and sitemaps submitted by webmasters.

  • After crawling, search engines index web pages to understand their content and relevance.

  • Ranking is the process of selecting and presenting search results based on various factors like keyword relevance and content quality.

  • Google's algorithms constantly update to improve search result quality and personalize results based on user behaviour, location, and language preferences.

  • Search engines personalize results to provide users with more relevant and localized information.

  • Personalization considers factors such as user location, language preference, and search history.

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