Search engines, such as Google, Bing or Qwant, allow Internet users to find information on the web quickly and efficiently. Their operation is based on two main processes: exploration and indexing.
Definition of a search engine
A search engine is a computer system that allows you to find resources (web pages, images, videos, documents, etc.) on the Internet based on specific criteria, usually in the form of keywords. They use complex algorithms to analyze and index billions of resources on the web to provide relevant results to the user.
Directory vs. search engine
Created in 1994, Yahoo! was one of the first directories on the web (directories list each site in a category submitted to them).
No real algorithm behind it, because few web pages in those years.
Today, Yahoo! has become a search engine.
Also created in 1994, Lycos was one of the first search engines.
Unlike directories, search engines automatically collect data from websites.
Today, Google dominates the market, followed by Bing.
The indexing process and output of the results
1/ Crawl
Crawl, also called “crawling,” is the automated process by which a search engine discovers and analyzes new web pages. It uses crawlers, also known as “spiders” or “crawlers”, which follow hyperlinks from one page to another to discover new content.
Crawlers identify web pages based on various criteria, such as keywords in the content, website structure, and external links from other trusted websites. They then store the information about these pages in a database called an “index”.
2/ Indexing
Indexing is the process of storing and organizing information collected during crawling. A search engine's index is a massive structure that contains information on billions of web pages. It allows the search engine to quickly and efficiently find relevant pages for a user query.
During indexing, crawlers analyze the content of web pages, such as keywords, titles, descriptions and hyperlinks. They also extract information about the structure of the website, when the page was published and other factors important for relevance.
This information is then stored in the index as inverse files, which allow the search engine to quickly find web pages containing specific keywords or matching other search criteria.
3/ Questioning
Querying is the process by which a user submits a query to a search engine. The query can consist of keywords, phrases or Boolean expressions. The search engine then uses its index to identify the web pages most relevant to the query.
When analyzing the query, the search engine takes into account several factors, such as the keywords used, user intent and the search context. It also uses complex algorithms to rank search results based on relevance, usefulness, and quality.
4/ Restitution
Rendering is the process by which the search engine presents search results to the user. Search results are typically displayed as a list of web pages, ordered by relevance. Each result typically includes the page title, a short description, and the page URL.
The search engine may also provide additional information about the results, such as images, text snippets or links to other related web pages. The objective of the restitution is to provide the user with the most relevant and useful information for their query.
SEO vs positioning
SEO is a term often used wrongly to talk about the visibility of a website through search engines.
- SEO is the process of indexing pages.
- Positioning corresponds to the position of the site when searching on a search engine.
Search engines in conclusion
Search engines have become essential tools for browsing the Internet and finding information. Their operation relies on a complex infrastructure and sophisticated algorithms. They help provide users with relevant and useful results.
In 2024, search engines continue to evolve to meet the growing needs of users. They incorporate new features, such as voice search, image search and semantic search, to provide a more intuitive and efficient search experience.
Esteban Irschfeld, SEO Consultant at UX-Republic
