Firstly, search engines crawl the web to gather information and build their database. This is done by an automated software called a search engine crawler or spider or a bot. These spiders crawl through a site and look at the content (mainly text) to know what the site is about and then start collecting, parsing and storing the data so that it can be easily be retrieved from its database.
However, since there are over billion pages on the web, it is practically impossible for a spider to revisit a site on a daily basis only to see if a new page has been added or an existing page has gone through any modification. Many times the spider may not visit your website for a month or more also, therefore, the true impact of SEO efforts cannot be known immediately.
It is also good to know that search engines are mainly text driven and are oblivious to images, sounds, flash movies, java script, frames, directories, and similar stuff. Therefore having lots of these on your website may not be very helpful from the SEO point of view as these will not be crawled and indexed for further processing.
Search Engine Indexing
Once a page is crawled, the next step involves indexing the content. This process entails finding those words that can best describe the webpage content and then assigning the webpage to specific keywords. The indexed page is then stored in the huge database for retrieval later. At times, the search engine may not be able to correctly identify the meaning of the page and in such a case optimization of the page can help it classify it rightly and achieve a better ranking for you.
This is done when a user enters a search query – in simple terms, the search engine analyses the information it has indexed in relation to the search request. Since there will be millions of pages containing the same search term, the search engine calculates the relevance of each page in its database to the search query.
The relevancy of a page is calculated based on various algorithms. These algorithms assign different weights for general aspects like Meta Tags, Keyword Density, and Links. However, one basic truth that you need to know is that all major search engines regularly change their algorithms and if you want to continue to appear on the top of the search results, you need to keep your pages up to date. Also, it would be a wise decision to think about SEO to rank on the top and also gain an edge over your competitors.
This is the last step in the process where the search engine retrieves the results, that is, it throws up all the relevant results before the user. The uses can see a vast pool of information related to their search query.
There may be questions regarding how differently each search engine functions. However, one basic thing that you need to know is that there are differences in the manner various search engines function but at the end of the day they all perform three fundamental tasks:
- Searching the Internet based on the search query entered by the user.
- Maintaining an index of all the information that gather from various pages.
- Permit users to search for words available in that index.