How Search Engines Work
Two of the biggest questions about SEO on the internet are: "What is the technology behind search engines?" and "What method do search engines like Google use to select the sites that rank highly in search results?" Here is some basic information that clarifies both points.
The technology behind seach engines
The hundreds of millions of sites, blogs and other pages that constitute the internet form a kind of spider web. Search engines wander around this web with a robot called a "spider'' or ''crawler" and collect information on websites they encounter. The information collected is stored in a database called an index. Search engines analyze information and verify the appropriateness and legality of the sites in accordance with their own evaluation criteria that are often kept secret.
When an internet user performs a keyword search, the search engine searches its index for the websites that are relevant to the keyword and displays sites in the list of results that a user sees when he clicks "Search." Businesses and other sites compete to earn top placement for certain keywords, as taking first position for competitive keywords is very lucrative.
Search engine positioning
The method that search engines use to select the websites that have the best positions in search results is a closely guarded secret, but thanks to some experts in SEO, we now know that the backlinks (inbound links), the content, the site's ''sitemap'' and over 50 other factors are all important in achieving top results. The first position is not special, however. High quality content and large amounts of backlinks are key to raising any site's visibility, even if that means getting from page four to page two.
While aggressive optimization and content changes are a great way to climb the ranks, there are certain things that webmasters must not do. The practice of "spamdexing" or putting up a bunch of low quality content with lots of advertising, or using doorway pages to trick the search engine into seeing content that is different from what the user sees, can get a site delisted from Google. Some SEO firms use these so-called "black hat" tactics, so ask questions before you buy.
Search engines have come a long way since the days of AltaVista and HotBot. That said, the goal is still the same: deliver quality content relevant to the user's search, so remember that content is king when embarking on any SEO endeavor.