Objection: But everyone knows how Google Search works, and everyone knows how to search for something on Google. Sure, but to do SEO, you need to delve a little deeper. For example, you need to know that search engines work by scanning billions of pages using web crawlers.

Crawlers, also known as spiders or bots, navigate the web and follow links to find new pages. These pages are then added to an index from which search engines pull results.

Put like that, it seems simple, but in reality it is an organized and very complex operation, performed by extremely sophisticated algorithms bordering on artificial intelligence.

1. Search Engine Basics

What are search engines?

Search engines are searchable containers of web content. They consist of two main parts: 

1. Search Index. A digital library of web page information. 
2. Search algorithms . Computer programs that rank matching results from a search index.

What is the purpose of search engines?

Every search engine aims to provide the best and most relevant results for users. This is partly how they gain market share.

How do search engines make money?

Search engines have two types of search results: 

1. Organic results from the search index. You can’t pay to be listed here.
2. Paid results from advertisers. You can pay to be listed here.

Every time someone clicks on a paid search result, the advertiser pays the search engine. This process is known as pay-per-click (PPC) advertising, which is why market share matters. More users mean more clicks on ads, and therefore more revenue for the search engine.

Paid results: Businesses pay Google to appear in these results.

Organic results : No one can pay Google to appear here.

2. How search engine indexes are built

Each search engine has its own process for building a search index. Here’s a simplified version of the process Google uses:

Let’s analyze this process to try to understand how it works.

URL

It all starts with the URL (Uniform Resource Locator), essentially the web address of a page on the Internet. Google discovers them in many ways, but the three most common are: 

• From backlinks. Google has an index of hundreds of billions (yes, billions) of web pages. If someone links to a new page from a page already known to Google, Google will start finding it there.
• From sitemaps. Sitemaps tell Google which pages and files you consider important.
• From URL submissions. Google allows site owners to request crawling of individual URLs through its Google Search Console .

Crawling (Scanning)

Crawling is the process by which a computer bot called a spider visits and downloads known URLs. Google’s crawler is Googlebot.

Processing and rendering

Processing is how Google understands and extracts key information from crawled pages. To do this, it must render the page, which essentially runs the page’s code to understand how users search. 

No one outside of Google knows every detail of this process, but that’s not important—what we really need to know is that it involves extracting links and storing content for indexing. 

Indexing

Indexing is the process by which information processed from crawled pages is added to the search index.

The search index is essentially what people look for when they use a search engine. That’s why being indexed by major search engines like Google and Bing is so important. Users can’t find you unless you’re included in the index. 

3. How pages are ranked by search engines

Discovering, crawling, and indexing content is just the first part of the puzzle. Search engines also need a way to rank matching results when a user performs a search. This is the job of search algorithms.

What are search algorithms?

Search algorithms are formulas that cross-reference and rank results they deem relevant from the index. Google uses many factors in its complex algorithms.

Key Google Ranking Factors

No one knows all of Google’s ranking factors because Google hasn’t disclosed them. But some key ones are known; let’s take a look.

Backlink

Backlinks are links from one page of a website to another. They are one of Google’s strongest ranking factors.

It’s not just about quantity, though; quality matters too. Pages with a few high-quality backlinks often outrank those with many low-quality backlinks.

Relevance

Relevance is the usefulness of a given result to those searching for it. Google determines this in several ways. At the lowest level, it searches for pages containing the same keywords as the search query, then it also examines interaction data to see if others found the result useful.

Freshness

Freshness is a query-dependent ranking factor. It’s strongest for searches that require new results.

Page speed

Page speed is a ranking factor on desktop and mobile. However, it’s more of a negative ranking factor than a positive one, as it negatively impacts slower pages rather than positively impacts faster ones.

Mobile-friendly

Mobile-friendliness has been a ranking factor on both mobile and desktop since Google moved to mobile-first indexing in 2019.

4. How search engine results are personalized

Google personalizes search results for each user. Information such as your location, language, and search history are used to personalize the results displayed for each user.

Position

Google uses your geographic location to personalize search results, aiming to offer the most locally relevant ones. That’s why, if we try to type “Italian restaurant,” we’ll see local restaurants closest to the location we’ve entered. Google’s assumption is that it’s unlikely that from a given geographic location, you’d fly halfway around the world for lunch.

Language

Google knows it doesn’t make sense to show results in English to Spanish or Italian users. That’s why it ranks localized versions of content (if any) for users who speak different languages.

Search history

Google saves the things you do and the places you go to offer you a more personalized search experience. You can opt out of this by opting out of cookies or by customizing Google’s privacy settings, but most people probably don’t care. 

Please remember:

• Search engines consist of two main parts: index and algorithms.
• To build their index, they crawl known pages and follow the links to find new ones. 
• The purpose of search algorithms is to return the best and most relevant results.
• The quality of search results is important for building market share.
• No one knows all of Google’s organic ranking factors.
• Key ranking factors include backlinks, relevance, and freshness. 
• Google personalizes results based on your location, language, and search history. 

I have read many SEO tutorials, but during my work, I had the feeling that the content of these tutorials and various guides is not organized, that there is no clear starting point towards SEO knowledge.

So I wrote this guide, with regularly updated articles, which can be useful both for those who are just starting to understand something or for those who already know the basics of SEO, but also for personal reference. (Note: some articles are still under review; you will find them published in the coming weeks.)

What is SEO?

SEO (Search Engine Optimization) is the practice of increasing a website’s traffic from organic search results. It involves things like keyword research, content creation, link building, and technical audits.

The Beginner’s Guide to SEO

These six chapters are all I think you need to build a foundation of SEO knowledge and start ranking your websites higher on Google.
Each chapter has links to many more advanced learning materials.

Chapter 1 – How Search Engines Work

Before starting with SEO, it’s important to understand how search engines work.

Chapter 2 – SEO Basics

Learn how to set up your website for success and excellent search engine rankings, and cover the four main aspects of SEO.

Chapter 3 – Keyword Search

The starting point in SEO is to understand what your customers, your target audience, are looking for.

Chapter 4 – SEO Content

Learn how to create content that rank well in search engines.

Chapter 5 – On-Page SEO

How to optimize your website pages to help search engines interpret and understand them well.

Chapter 6 – Creating Links (Links – Backlinks)

Links are how search engines discover new pages and judge their authority. It’s difficult to be competitive without links.

Chapter 7 – SEO Technique

It is important not to make mistakes or missteps that prevent Google from accessing and understanding your website,

SEO Glossary

SEO has a lot of technical jargon, and in this glossary I’ve listed some key terms and concepts you should know.

Backlinks: Links from one page on a website to another.

Keywords : The words and phrases that people type into search engines to find what they are looking for.

Long-tail keywords : Keywords with low search volumes.

SERP : This stands for Search Engine Results Pages. These are the pages that Google and other search engines display in response to a user’s search query.

SERP Features : Non-traditional search results (not a “blue link”) such as videos, tweet boxes, or featured snippets.

Featured Snippets: Search query answers extracted from a top-ranking page that appears near the top of the SERP.

Rich snippets : Search results with additional valuable information displayed next to them (e.g., star ratings, cooking times, etc.)

Outreach : Send emails to relevant bloggers and journalists to tell them about your content.