The first basic truth you must know to learn SEO is that yahoo are not humans. While this will likely be obvious for everybody, the differences between how humans and yahoo view web pages aren't. Dissimilar to humans, search engines are text-driven. Even if technology advances rapidly, search engines are definitely not intelligent creatures that can feel the beauty of a cool design or see the sounds and movement in movie channels. Instead, search engines crawl the online market place, looking at particular site items (mainly text) to find an idea what a site is going. This brief explanation is not the foremost precise because as we will see next, search engines perform several activities that allows you to deliver search results -crawling, indexing, handling, calculating relevancy, and retrieving.
First of all, search engines crawl the Web to work out what is there. This task is performed by a joint of software, called acrawler or a fabulous spider (or Googlebot, as certainly is the case with Google). Spiders follow links in one page to another and index everything they find on the way. Having in mind the numerous pages on the Web (over 20 billion), it's always impossible for a spider to inspect a site daily just to work out if a new page has appeared or if an existing page has been modified, sometimes crawlers may not lead to visiting your site for a couple of months.
From page is crawled, the next thing is to index its content and articles. The indexed page is stored within the giant database, from where it may well later be retrieved. Essentially, the job of indexing is identifying the words and expressions that best discuss the page and assigning all the page to particular keywords. For a human you will not regret be possible to process such variety of information but generally search engines deal just fine this particular task. Sometimes they might not take advantage of the meaning of a page right but once you help them by optimizing the software, it will be easier from which classify your pages correctly and for your needs - to get higher position.
Every search request comes, the online search engine processes it - i. ice. it compares the search string on the search request with the indexed pages on the database. Since it is likely that dozens page (practically it is enormous pages) contains the search chain, the search engine starts calculating the relevancy of each one of the pages in its index along with the search string.