How Search Engines Work?

The purpose of this article is to provide you with a quick introduction to how search engines work.

We all use google. We've used it thousands of time so far, just to find answers and information, we didn't care about how it works. Now it's the time to dive in this part, that's why you clicked this link, right? You want to know how this giant called Google (and other search engines) work. Getting a glance on this process will help you to get an idea of what to need to achieve with SEO.

Search engines play a huge role in our daily life, on the way we get information or buy things. Whenever we have a question, the first thing we do it to open Google and do that search either by typing in the search box or through voice search. We expect to find what we're looking for in seconds and mechanically we click one of the top results given by the Google Search.

This translates into: 

Google has to respond fast to every search request and provide with accurate results, therefore they have to do a lot of preparation work in advance.

This process is broken down into 2 major steps:

• Crawling and Indexing
• Ranking process (search algorithms)

Crawling and Indexing

Throughout this process, Google creates an index of ALL the websites that are publicly available on the Internet.

Consider this as a telephone catalog but much bigger and instead of keeping names and telephones it keeps key information about a web site.

Webpages that have been discovered by the search engine are added into a data structure called an index. The index includes all the discovered URLs along with a number of relevant key signals about the contents of each URL such as:

• The keywords discovered within the page’s content – what topics does the page cover?
• The type of content is being crawled – what is included on the page?
• The freshness of the page – how recently was it updated?
• The previous user engagement of the page and/or domain – how do people interact with the page?

To achieve this, Google has a number of programs called spiders (aka crawlers or bots) that crawl the web, collect and enter this information in the Google database for additional processing.

The crawlers are responsible for both finding new pages and monitoring existing pages for changes.

Over the years Google has become remarkably good at this and they can identify and index important information almost instantly.

Google has hundreds of spiders monitoring the web and an enormous database of storing and processing all the information.

Ranking Process and Search Algorithms

The mission of search algorithms that run through the ranking process is to make able for Google to give you a direct answer or present you with a list of websites that are most likely to satisfy your request, every single time you type a query into the Google search box.

Search algorithms are complex computer programs that analyze the data in the Google index and make decisions as to which websites to show in the results for any given query, and at what order.

The initial algorithm was created back in 1996, by the Google founders (Larry Page and Sergey Brin). At the beginning the algorithm was simple but over the years it has become very complex. It is believed that it takes more than 255 factors into account before making a decision.

Recently Google incorporated their Artificial Intelligence (AI) technology into the search algorithm so now the ranking decisions are made by both robots and the logic that is maintained by humans.

There have been many engineers who tried to decrypt the algorithm and understand exactly how ranking works but... it still remains Google’s precious secret!

Though, there are some known factors that Google admitted that are part of the algorithm (like page speed, information security (SSL) and mobile-friendliness) but the rest were never officially released or admitted by Google.

One of the main goals of SEO is to present Google with the right signals so that during the ranking process, the search algorithm will ‘pick up’ your site and show it on top of the search results.

What about BING and other search engines?

Google it might be the most popular search engine with more than 60% market share but it’s not the only one. There are other search engines like Bing, Yandex, duckduckgo that hold the other 40% of the market.

In general, whatever optimization changes you make to your website to satisfy the search giant will help your rankings in other search engines as well.