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Search engines work by crawling billions of pages using web crawlers Robots, also known as spiders or bots, navigate the Internet and follow links to find new pages. These pages are then added to the index from which the search engine pulls the results.
If you are doing SEO, it is necessary to understand how search engines work. After all, it’s hard to optimize something if you don’t know how it works.
This article describes the stages in which search works in the context of your site. With this basic knowledge, you can fix crawl problems, index pages, and learn how to improve your site’s appearance on Search Engines, especially on Google.
Three Stages Of How Search Engines Work?
Search engines primarily work in three stages, but not all the pages necessarily pass through each stage.
Crawling: search engines pull text, images, and videos from the pages it finds on the Internet using automated programs called robots.
Indexing: Search engines analyze the text, image, and video files on a web page and store the information in the search index, a massive database.
Serving search results: When a user searches on a search engine, it returns information relevant to the user’s search query.
Let’s discuss each stage in detail to understand the search engine functionality.
Search Engine Crawling
Crawling is a search process in which search engines like Google constantly send robots (also known as crawlers or spiders) to find new and updated content and add them to the list of known sites. This content could be a page, video, image, PDF, etc. This process is called URL discovery.
Googlebot starts fetching some web pages, then follows the links on those web pages to find new URLs. By following these links, the crawlers (also known as a robot, a bot, or a spider) find new content and add it to their index database of discovered URLs for later retrieval when searchers look for information that the URL content matches.
Googlebot uses algorithms to determine which websites to crawl, how often, and how many pages to fetch from each website. Google’s robots are also programmed to try not to crawl sites too fast so as not to overload them.
However, Googlebot does not crawl all the pages it finds. Some pages may not be allowed to be crawled by the site owner, and other pages may be duplicates of previously crawled pages. There are also a few pages that are not accessible to crawl without logging in to those pages.
Crawling relies on Google robots having access to the site. Some of the common problems when Googlebot accesses websites are:
- Network issues
- Problems with the server managing the site
- The robots.txt command prevents Googlebot from accessing the page
Search Engine Indexing
Once a search engine crawls a web page, Google tries to find out what that page is about, and adding it to the search index is called Indexing. It is a process and analysis of textual content and key content tags and attributes such as <title> elements and alt attributes, images, videos, etc
The search index is what you search for when you use a search engine. So, Indexing on all major search engines, like Google, Bing, and Yahoo too important as searchers can only find those pages that are indexed.
During the indexing process, Google determines whether a page is a duplicate of another page on the web or canonical. Canonical is a page that can appear in search results. To choose the canonical one, Google first group the pages to find on the web that has similar content and then select the one that best represents the group.
Information collected about the canonical page and its clusters can be stored in the Google index, a large database hosted on thousands of computers. Every page crawled by Google is not guaranteed to be indexed.
Indexing also depends on the Metadata and content of the page. Some common indexing issues can be:
- Low page content quality
- Robots meta directive prohibits indexing
- Website design can make indexing difficult
Search Engine Ranking
When someone performs a search, search engines scan their index for highly relevant content and then rank that; content to present the best result to the user’s search query. This sorting of search results by relevance is called ranking. In general, you can assume that the higher the ranking of a website, the more relevant search engines perceive that website to be to a search query.
Search Console may tell you that the page is indexed, but you don’t see it in search results. It is due to the bellow mentioned issues.
- The content of the page is irrelevant to a user search query.
- The quality of the content is significantly low.
- Robots’ meta directives prevent serving.
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