Chapter 1. SEO Foundation

How Do Search Engines Work and What Is Ranking Algorithm?

Before learning SEO, it is imperative to establish a comprehensive understanding of Search Engines. Everyone uses search engines, but only a few people can really answer, "How do search engines work?". Despite the simplicity of entering a search and getting results, the inner workings are complex. We'll explore the behind-the-scenes, like how search engines crawl the web, index information, and use algorithms to give you the results you see.

Google's Search Engine Market Share

According to GlobalStats, Google maintains more than 90% of the search engine market share globally. Based on this fact, you must first understand Google's search engine.

Google’s Global Search Engine Market Share

Other search engines besides Google include Bing by Microsoft, Yahoo, Baidu, and Yandex. The core principles of SEO can also be applied across various search engines, although each has unique characteristics in its algorithm, crawling and indexing approaches, and user demographics.

How Do Search Engines Work?

As shown in the main figure, we can explain how search engines work from two perspectives.

How do search engines work from the user's point of view?

From the user's point of view, the way search engines work is very simple.

First, a user enters a Search Query (a specific set of words or phrases entered into a search engine to find information).

Second, the user will get the search results on the SERP (Search Engine Result Page).

Note: SERP (Search Engine Result Page)

SERPs do not only display organic search results with text and URLs.

Nowadays, SERPs show information related to the searched keywords in various formats. Here are examples of the key forms of information on SERPs.

SERP (Search Engine Result Page)

The image above illustrates an example of SERP. The main part of SERP is Organic Search Results. Google's ranking algorithm orders the results, considering several factors. We'll explain the ranking algorithm later in this learning section.

The Google Ads platform also connects with SERPs. If advertisers bid on the searched keywords, Paid Ads (marked as "Sponsored") may appear below the search bar.

The SERP may also display several Featured Rich Results. To learn more about these results, check What Is Schema in SEO? | Structured Data and Rich Results.

How do search engines work behind the scenes?

While the search engine looks very simple from the user's perspective, Google does a lot of work behind the scenes.

Here are the simplified explanations of the search engine mechanism:

Crawling

First, Google uses automated bots (called crawlers or Googlebots). These bots regularly and systematically browse web pages on the internet across the world to collect and assess the information each web page provides.

Indexing

The content of the crawled pages is parsed (analyzed). Then, the relevant text content is extracted from the parsed information and added to Google's index, a massive database that stores details about the content and structure of web pages.

Ranking Algorithms

When a user enters a search query, the search engine uses a ranking algorithm to evaluate and rank the indexed pages based on various factors.

To understand how the Google search engine works, check Google's official documentation – In-depth guide to how Google Search works.

Search Ranking Results - Ranking Algorithms

Search ranking results for the keywords are calculated by highly sophisticated and complex systems. Google uses several automated ranking systems that look at many factors and signals (check "A guide to Google Search ranking systems").

There is no comprehensive official documentation of the ranking algorithms in detail; however, Google briefly explains how their website automatically generates results (check "Ranking Results – How Google Search Works").

Understanding how search results are generated is crucial for effectively designing and executing SEO approaches.

Here is the summary of the explanation on Google's official web page:

Google’s Ranking Result Factors from Google’s Official Site

Meaning of your query

To understand and fulfill the search query, Google employs sophisticated language models that decipher the intent behind the entered words.

This involves recognizing and correcting spelling mistakes, utilizing a synonym system for semantic connections, etc.

Relevance of content

Google evaluates content relevance by analyzing keywords and considering various factors.

Essential signals include search query keywords on web pages, headings, or text body.

Beyond this, Google uses aggregated interaction data to refine relevance estimation, transforming it into signals for machine learning systems.

Quality of content

After identifying relevant content, Google prioritizes it based on signals indicating expertise, authoritativeness, and trustworthiness.

Factors include assessing links from prominent websites, a sign of well-trusted information.

Google constantly evaluates system quality to maintain user trust in search results by balancing information relevance and authoritativeness.

Usability of webpages

Google considers the usability of content. When all other factors are relatively equal, content that people find more accessible may perform better.

Page experience is important. For example, Google prioritizes mobile-friendly content and quick loading times to ensure a positive page experience on mobile devices.

Context and settings

Contextual information such as location, search history, and settings enhance personalized search results.

Search settings, like preferred language or SafeSearch preferences, influence search results.

Personalization extends to Google account activity, recommending events based on interests.

While designed to match user interests, systems avoid inferring sensitive characteristics like race or religion.

Users have control over Search activity for a customized experience, managing data saved to their Google account.

The Google 200 Ranking Factors Myth

Although Google's specific ranking algorithm is proprietary and its exact details are not publicly disclosed, the idea of 200 ranking factors is often discussed among the SEO professional community.

We categorized the numerous potential ranking factors into 8 groups based on several sources, including Google’s 200 Ranking Factors: The Complete List and Your Cheat Sheet to Google's 200 (Known) Ranking Factors.

Search Engine Ranking Factor Comprehensive Categories

1. Page-level relevance, quality and performance

There are many ranking factors among the page-level factors. Here are the essential subcategories. These ranking factors should be addressed through on-page SEO and technical SEO.

Relevance to Query:

The primary consideration is how well a specific page matches the user's search query. Pages with content directly addressing user intent and providing relevant information are more likely to get a higher ranking.

Keyword optimization plays a critical role in demonstrating the page's relevance to the query. Pages optimized for relevant keywords are more likely to rank higher.

Content Quality:

High-quality content is one of the most crucial factors for getting higher ranks.

High-ranked pages should provide accurate, engaging, comprehensive, and original information to satisfy user's search intent.

Link Quality and Relevance:

Linking to authoritative and relevant sites can be positive signals for improving the page's authority.

Page Experience:

Page experience in the SEO context refers to the overall user experience and satisfaction when interacting with a web page.

Page experience has three key elements: speed, mobile-friendliness, and security.

Google uses Core Web Vitals to assess page speed, including LCP (Largest Contentful Paint), INP (Interaction to Next Paint), and CLS (Cumulative Layout Shift).

2. Site-level relevance, quality and performance

Site-level factors can be aggregations of page-level factors, but site-specific factors also exist. Here are the essential subcategories. These ranking factors should be addressed through on-page SEO and technical SEO.

Site architecture, usability, and crawlability

Website structure is important for both users and crawlers. A well-structured website can improve its usability and crawlability.

Having additional structured information also helps users and crawlers to understand the site structure, such as sitemap (HTML sitemap and XML sitemap) and breadcrumbs (HTML-based and schema markup).

Duplicated content on the same website can be negatively rated.

Site reliability and relevance to Query

Google emphasizes the E-E-A-T (Experience, Expertise, Authoritativeness, and Trustworthiness) concept to provide relevant and accurate information to users for the query.

Having only one web page may not be sufficient to demonstrate E-E-A-T on a particular topic. To demonstrate the reliability of your website, you may need to have multiple pages covering related topics comprehensively.

Site's Technical Performance

Security, speed, and mobile-friendliness are also applicable at the site level.

Google mentions that using HTTPS is an essential factor and is usually managed at the site level.

The use of CDN or optimization of server location to improve speed should also be handled at the site level.

3. Domain authority

Although Google's explanation of the Ranking Results does not directly mention a domain, a domain influences ranking results.

Domain Authority (DA) is a search engine ranking score developed by Moz, but the idea of domain authority is widely used in the SEO professional community. Higher domain authority has a positive impact on getting higher search rankings.

Building domain authority takes time and requires all three types of SEO: on-page SEO, technical SEO, and off-page SEO.

4. Backlink quality and quantity

Backlinks are critical to demonstrate the web page's relevance to the query and the quality of content. Good backlinks from reputable websites are better for improving ranking than having lots of low-quality backlinks.

The way backlinks to your website appear is also important, such as the anchor text used in the backlink and where the link is located in the content of the referring website. The search engine may penalize paid backlinks (see spam detection section below).

Backlink building is the core part of off-page SEO.

5. Brand and social signals

Brand and social signals can be used to assess the website's or page's reputation. Highly reputed websites can demonstrate E-E-A-T to search engines. You can address brand and social signals through Off-Page SEO and On-Page SEO.

6. User engagement

How your page attracts and engages users is important for Google to measure if it satisfies the user's search intent.

SEO experts discuss various methods of measuring user engagement for ranking. These methods include organic CTR (Click-Through Rate), bounce rate, dwell time, direct traffic, and repeat traffic.

You can address user engagement issues through on-page SEO and technical SEO.

7. User context and settings

Google states that factors such as user location, search history, and personalized settings influence the ranking of search results.

You cannot control the user's context and settings. However, using SEO techniques, you can optimize content and website configurations for the user.

Check Geographical SEO Context: Local SEO and International SEO for geographical context.

8. Spam detection

Google invests heavily in spam detection. Its official page says, " In 2020 alone, our systems found 40 billion spammy pages every day."

Web pages suspected of being potential spam are negatively rated. Google's spam policies are also available on the official page.

Conclusion

In this learning section, you have learned how search engines work and what ranking factors are used by ranking algorithms.

When you are becoming more familar with SEO, you may notice that several factors depend on other factors. For example, better page quality and performance can positively impact user experience, and high-quality backlinks will help build domain and page authority.

Ultimately, the important thing is to understand where effective control points for SEO approaches are. In the following learning sections, we will explore how you can positively impact key ranking factors through your SEO efforts.


You can also learn this topic on Kindle. ClickAmazonKindle.

Before learning SEO, it is imperative to establish a comprehensive understanding of Search Engines. Everyone uses search engines, but only a few people can really answer, "How do search engines work?". Despite the simplicity of entering a search and getting results, the inner workings are complex. We'll explore the behind-the-scenes, like how search engines crawl the web, index information, and use algorithms to give you the results you see.

Google's Search Engine Market Share

According to GlobalStats, Google maintains more than 90% of the search engine market share globally. Based on this fact, you must first understand Google's search engine.

Google’s Global Search Engine Market Share

Other search engines besides Google include Bing by Microsoft, Yahoo, Baidu, and Yandex. The core principles of SEO can also be applied across various search engines, although each has unique characteristics in its algorithm, crawling and indexing approaches, and user demographics.

How Do Search Engines Work?

As shown in the main figure, we can explain how search engines work from two perspectives.

How do search engines work from the user's point of view?

From the user's point of view, the way search engines work is very simple.

First, a user enters a Search Query (a specific set of words or phrases entered into a search engine to find information).

Second, the user will get the search results on the SERP (Search Engine Result Page).

Note: SERP (Search Engine Result Page)

SERPs do not only display organic search results with text and URLs.

Nowadays, SERPs show information related to the searched keywords in various formats. Here are examples of the key forms of information on SERPs.

SERP (Search Engine Result Page)

The image above illustrates an example of SERP. The main part of SERP is Organic Search Results. Google's ranking algorithm orders the results, considering several factors. We'll explain the ranking algorithm later in this learning section.

The Google Ads platform also connects with SERPs. If advertisers bid on the searched keywords, Paid Ads (marked as "Sponsored") may appear below the search bar.

The SERP may also display several Featured Rich Results. To learn more about these results, check What Is Schema in SEO? | Structured Data and Rich Results.

How do search engines work behind the scenes?

While the search engine looks very simple from the user's perspective, Google does a lot of work behind the scenes.

Here are the simplified explanations of the search engine mechanism:

Crawling

First, Google uses automated bots (called crawlers or Googlebots). These bots regularly and systematically browse web pages on the internet across the world to collect and assess the information each web page provides.

Indexing

The content of the crawled pages is parsed (analyzed). Then, the relevant text content is extracted from the parsed information and added to Google's index, a massive database that stores details about the content and structure of web pages.

Ranking Algorithms

When a user enters a search query, the search engine uses a ranking algorithm to evaluate and rank the indexed pages based on various factors.

To understand how the Google search engine works, check Google's official documentation – In-depth guide to how Google Search works.

Search Ranking Results - Ranking Algorithms

Search ranking results for the keywords are calculated by highly sophisticated and complex systems. Google uses several automated ranking systems that look at many factors and signals (check "A guide to Google Search ranking systems").

There is no comprehensive official documentation of the ranking algorithms in detail; however, Google briefly explains how their website automatically generates results (check "Ranking Results – How Google Search Works").

Understanding how search results are generated is crucial for effectively designing and executing SEO approaches.

Here is the summary of the explanation on Google's official web page:

Google’s Ranking Result Factors from Google’s Official Site

Meaning of your query

To understand and fulfill the search query, Google employs sophisticated language models that decipher the intent behind the entered words.

This involves recognizing and correcting spelling mistakes, utilizing a synonym system for semantic connections, etc.

Relevance of content

Google evaluates content relevance by analyzing keywords and considering various factors.

Essential signals include search query keywords on web pages, headings, or text body.

Beyond this, Google uses aggregated interaction data to refine relevance estimation, transforming it into signals for machine learning systems.

Quality of content

After identifying relevant content, Google prioritizes it based on signals indicating expertise, authoritativeness, and trustworthiness.

Factors include assessing links from prominent websites, a sign of well-trusted information.

Google constantly evaluates system quality to maintain user trust in search results by balancing information relevance and authoritativeness.

Usability of webpages

Google considers the usability of content. When all other factors are relatively equal, content that people find more accessible may perform better.

Page experience is important. For example, Google prioritizes mobile-friendly content and quick loading times to ensure a positive page experience on mobile devices.

Context and settings

Contextual information such as location, search history, and settings enhance personalized search results.

Search settings, like preferred language or SafeSearch preferences, influence search results.

Personalization extends to Google account activity, recommending events based on interests.

While designed to match user interests, systems avoid inferring sensitive characteristics like race or religion.

Users have control over Search activity for a customized experience, managing data saved to their Google account.

The Google 200 Ranking Factors Myth

Although Google's specific ranking algorithm is proprietary and its exact details are not publicly disclosed, the idea of 200 ranking factors is often discussed among the SEO professional community.

We categorized the numerous potential ranking factors into 8 groups based on several sources, including Google’s 200 Ranking Factors: The Complete List and Your Cheat Sheet to Google's 200 (Known) Ranking Factors.

Search Engine Ranking Factor Comprehensive Categories

1. Page-level relevance, quality and performance

There are many ranking factors among the page-level factors. Here are the essential subcategories. These ranking factors should be addressed through on-page SEO and technical SEO.

Relevance to Query:

The primary consideration is how well a specific page matches the user's search query. Pages with content directly addressing user intent and providing relevant information are more likely to get a higher ranking.

Keyword optimization plays a critical role in demonstrating the page's relevance to the query. Pages optimized for relevant keywords are more likely to rank higher.

Content Quality:

High-quality content is one of the most crucial factors for getting higher ranks.

High-ranked pages should provide accurate, engaging, comprehensive, and original information to satisfy user's search intent.

Link Quality and Relevance:

Linking to authoritative and relevant sites can be positive signals for improving the page's authority.

Page Experience:

Page experience in the SEO context refers to the overall user experience and satisfaction when interacting with a web page.

Page experience has three key elements: speed, mobile-friendliness, and security.

Google uses Core Web Vitals to assess page speed, including LCP (Largest Contentful Paint), INP (Interaction to Next Paint), and CLS (Cumulative Layout Shift).

2. Site-level relevance, quality and performance

Site-level factors can be aggregations of page-level factors, but site-specific factors also exist. Here are the essential subcategories. These ranking factors should be addressed through on-page SEO and technical SEO.

Site architecture, usability, and crawlability

Website structure is important for both users and crawlers. A well-structured website can improve its usability and crawlability.

Having additional structured information also helps users and crawlers to understand the site structure, such as sitemap (HTML sitemap and XML sitemap) and breadcrumbs (HTML-based and schema markup).

Duplicated content on the same website can be negatively rated.

Site reliability and relevance to Query

Google emphasizes the E-E-A-T (Experience, Expertise, Authoritativeness, and Trustworthiness) concept to provide relevant and accurate information to users for the query.

Having only one web page may not be sufficient to demonstrate E-E-A-T on a particular topic. To demonstrate the reliability of your website, you may need to have multiple pages covering related topics comprehensively.

Site's Technical Performance

Security, speed, and mobile-friendliness are also applicable at the site level.

Google mentions that using HTTPS is an essential factor and is usually managed at the site level.

The use of CDN or optimization of server location to improve speed should also be handled at the site level.

3. Domain authority

Although Google's explanation of the Ranking Results does not directly mention a domain, a domain influences ranking results.

Domain Authority (DA) is a search engine ranking score developed by Moz, but the idea of domain authority is widely used in the SEO professional community. Higher domain authority has a positive impact on getting higher search rankings.

Building domain authority takes time and requires all three types of SEO: on-page SEO, technical SEO, and off-page SEO.

4. Backlink quality and quantity

Backlinks are critical to demonstrate the web page's relevance to the query and the quality of content. Good backlinks from reputable websites are better for improving ranking than having lots of low-quality backlinks.

The way backlinks to your website appear is also important, such as the anchor text used in the backlink and where the link is located in the content of the referring website. The search engine may penalize paid backlinks (see spam detection section below).

Backlink building is the core part of off-page SEO.

5. Brand and social signals

Brand and social signals can be used to assess the website's or page's reputation. Highly reputed websites can demonstrate E-E-A-T to search engines. You can address brand and social signals through Off-Page SEO and On-Page SEO.

6. User engagement

How your page attracts and engages users is important for Google to measure if it satisfies the user's search intent.

SEO experts discuss various methods of measuring user engagement for ranking. These methods include organic CTR (Click-Through Rate), bounce rate, dwell time, direct traffic, and repeat traffic.

You can address user engagement issues through on-page SEO and technical SEO.

7. User context and settings

Google states that factors such as user location, search history, and personalized settings influence the ranking of search results.

You cannot control the user's context and settings. However, using SEO techniques, you can optimize content and website configurations for the user.

Check Geographical SEO Context: Local SEO and International SEO for geographical context.

8. Spam detection

Google invests heavily in spam detection. Its official page says, " In 2020 alone, our systems found 40 billion spammy pages every day."

Web pages suspected of being potential spam are negatively rated. Google's spam policies are also available on the official page.

Conclusion

In this learning section, you have learned how search engines work and what ranking factors are used by ranking algorithms.

When you are becoming more familar with SEO, you may notice that several factors depend on other factors. For example, better page quality and performance can positively impact user experience, and high-quality backlinks will help build domain and page authority.

Ultimately, the important thing is to understand where effective control points for SEO approaches are. In the following learning sections, we will explore how you can positively impact key ranking factors through your SEO efforts.


You can also learn this topic on Kindle. ClickAmazonKindle.