A guide to search engines: crawling, indexing and ranking

Search engines crawl the web to store and index pages in a database, and they also provide search interfaces so that we can access mankind’s vast knowledge base called the Internet.

Google has become a verb and a synonym for Internet search. Yet there were search engines on the Internet before Google, and the undisputed leader in search marketing has competitors around the world.

Microsoft’s Bing has taken up the fight again, and while Russia’s Yandex and Czech Seznam are feeling the heat from Google, Baidu has just as strong a footing in China as Google does in the Western Hemisphere.

Presentation: what is a search engine?

Search engines are the doors you walk through to access the World Wide Web. It’s a human-machine interface, if you think of the internet as a machine. A search engine is an interface that allows you to find your way around the Internet, find answers to your questions and, increasingly, find products or services to buy.

In the future, a search engine could be your AI-driven, voice-activated personal assistant, helping you organize not just information, but also appointments, travel, shopping, and your health.

A search engine is structured around a query, also called a keyword or search term, and a search engine results page, or SERP for those in the know. There is a high concentration of clicks at the top of search results. There are several reasons for this.

Only a limited number of results can be displayed in the interface, and when a result is offered first, many people will click on it rather than bother to read the others. Also, people tend to trust rankings. If a search engine places a page in first position, it assumes that it is probably the best.

This has created a paid search advertising business model at the top of the SERPs and an entire industry of search marketers working on ranking web pages as high as possible in those search results. This work is done by our dear friends, SEOs, who if you care about search engines, you’ll probably know it’s short for Search Engine Optimization.

How do search engines work ?

A search engine is highly sophisticated software that manages massive amounts of data and processes it with advanced algorithms incorporating increasing amounts of artificial intelligence (AI).

The basic functions of a web search engine are:

  • explore the web
  • Storing web pages in a database
  • Content indexing
  • Provide a search interface

explore the web

One of the main functions of a search engine is to “crawl” the Internet. The term comes from the fact that the search engine would move from page to page on the web to collect data. It would crawl through all the content and identify all the links, then start visiting each of those links – a movement depicted as a spider crawling the World Wide Web.

In the early days of Internet research, you had to submit your website to search engines so that they would find your pages. Today, Google’s web crawling is so efficient that it will find your website shortly after a link from another page points to it.

Web page storage

The search engine collects information from the pages it finds and stores it in aggregate form in a database. Early search engines only stored parts of the page or just meta information (information about information) hidden in the page header. Today, the norm is to collect all content. Search engines store truly big data in their effort to cover the entire internet.

Content indexing

The search engine goes through a process of indexing the website to create an easily accessible index of content. It uses a technique known as inverted indexing in which it will categorize web pages under searchable entries such as keywords, topics, or entities. This will allow it to find and display relevant data much faster than if it had to wade through all the content on every query.

Search interface

A search interface allows search engines to enter and interpret keyword queries and render a search results page with the results of the inverted index. The search interface consists of a query field, which is a form where you enter a keyword search and press a button to jump to a results page showing you content, or links to content, and providing the most relevant results the search engine could find.

A screenshot of a 2004 Google search page from the Wayback Machine.

Google was initially just a search box with two buttons. Pressing the “Google Search” button would bring up the search results page, and pressing the “I’m lucky” button would take you to the first result in the list. Image source: author

What is Search Engine Optimization?

Top positions in search results have become a priority goal due to the laziness of search engine users who click on the first result and trust the algorithm to deliver the best result at the top of the page. Search engine rankings have become prime time on the internet – the place to be when users search with a keyword relevant to your business.

The SEO industry emerged long before search engines found their business model with paid search. SEOs would research, test, and learn how to improve web pages to rank first for the most relevant keywords.

SEO is based on three pillars: architecture, content and authority. Architecture covers the technical dimension of your website, i.e. its response time, page and link structures, header components and meta tags.

The Content dimension covers keywords and website content. SEOs will do research to find the best keywords to rank for, then create or commission well-structured content for those keywords. The Authority dimension relates to how your site is seen from the outside, the strength of the brand and the links pointing to the site.

An illustration of the three pillars of SEO: Architecture, Content, Authority and the tools that support them.

There are tools for each of the three pillars of SEO, and there are tools that monitor and measure market strengths and performance. Image source: author

Search engine analysis covers the different approaches shown in the illustration above: site crawling, keyword research, content optimization, backlink analysis, ranking monitoring and various market trends and analysis approaches competitive. To learn more about SEO tools, check out The Ascent’s reviews of some of the leading SEO software solutions on the market.

7 alternatives to Google for users to find your content

Although Google is considered the number one search engine in the world, it is not the only player in the market and has various competitors around the world. Let’s see who they are below:

  1. Bin: Microsoft’s search engine is a follower in many ways, but it’s backed by exceptional technology and ambition. It is also a white label filler for various search properties around the world.
  2. DuckDuckGo: A small US-based search engine that does not track users or filter search results.
  3. Baidu: The Chinese search engine created by Robin Li, the man who created the Rankdex algorithm that inspired Google. Baidu is the leading search engine in China.
  4. Yandex: Yandex, which stands for “Yet Another Index”, was created in Russia and mainly covers Russia and countries of the former Soviet Union. The only other addition is Turkey, where Yandex has managed to compete with Google.
  5. Ship: A South Korean search engine that dominates the local market there.
  6. Yahoo! : Yahoo! was the most important entry point to the Internet. It used Google as a filler but was overtaken by its former service provider. Yahoo! Japan is different from Yahoo! and a major search engine in this market.
  7. Qwant: A French search engine with the ambition to attract users with an excellent user experience and similar privacy protections as DuckDuckGo. However, Qwant remains at a low level of penetration.

Step through the search engine door to knowledge

Search engines are among the most advanced technical solutions the world has ever seen and are the backbone of the businesses of Google, Yandex, Baidu and Microsoft. They allow users everywhere to access more information than anyone could have imagined.

Over time, the nature of search should evolve into more natural interfaces such as voice and images, but today it is still primarily keyword and text-based.

Search engine marketing, with its dual dimension of SEO and paid search, is one of the most dominant and powerful digital marketing channels. Research offers a truly magical solution to accessing the vast amounts of data available on the Internet and has helped create an economic model for the Web. Just Google to find out more.

Rosemary S. Bishop