A search engine is a tool that gathers the information shown on the web and then distributes it to the users through a process called crawling, in which the crawlers qualify the content saved on the web. Search engines use keywords to target the information a user is asking for.
Search engines are designed to organize, distribute and make easier the access to the information on the web required by a user when he asks a question or doubt on the keyboard of said search engine; a search engine can complete this process through a list of primary functions.
Crawling is the process where search engines use the famous ‘crawlers’ or ‘spiders’ that are nothing more than discovery robots to investigate and fresh content; crawlers can investigate from media files such as images or videos to complete webpages. This job is done through the use of links. Spiders find a website, and the proceeds follow any link that they can find on it.
In this process, the search engine stores and organizes the information found on the website by the crawlers in a database known as index. When a page is registered in the index, it means the crawlers found its content good enough to be shown to the users.
The moment a user makes a consult to a search engine, this immediately processes the keywords and proceeds to look in its index for what the most useful results could be and then show it to the user; this is known as ranking.
And besides these three, there are other two secondary functions a search engine can work with:
A scheduler determines the number difference between known and fresh URLs, and it then decides when to crawl new links or re-crawl old ones.
The crawler or spiders will send the links and information they acquired to a parser, who will send the extracted URLs to the index.
Search engines act as a filter to the enormous quantity of information that can be found on the web. They help the user to find the better result for the search he is doing and prevent him from having to browse by numerous and irrelevant sites or pages; search engines can do this by using the complex process and algorithms explained above, this with the purpose of showing the user not what marketers could want him to see, but what he really needs and is looking for.
If crawling and indexing content are both processes, search engines are used to divide and organize the content before it is shown to the user; ranking is the final step a website has to go through before reaching SERPs (search engines results pages). The algorithm is the process used to complete the ranking cycle, and each search engine has unique algorithms for ranking websites.