Search engines need to process millions of websites. The key to mastering SEO is knowing how a search engine reads your website’s content and processes it for a relevant web search.
One problem in trying to understand how a search engine works is the fact that they continuously change
The first task of a search engine is to find the websites and webpages it needs to index. This is done using a type of software robot called a spider
Each search engine, when a user makes an enquiry, refers to the word lists compiled by the spiders. Some search engines like AltaVista will list every word on every page, while others, like Google, list only tags and Meta tags. Others will base their decisions on keywords.
An important way a spider moves from one website to another is by links. When a website is linked to another, the spider follows the link and then records all the information on the new site. Once a search engine has an index it then ranks the sites and pages. This is done by looking at keyword density or it might be based on a system of weighting. The latter varies from search engine to another, but is used as a quality control filter. This means some search engines might give better index
ranking positions to academic sites than say to blogs on the same
subjects. Weighting can also be applied negatively to sites that the
search engine deems to be a spam site. All this depend to the
content, it is genuine or copied or…..