SEO: How does Google work?

Google indexes pages on the Web by using what are commonly known as "spiders", "crawlers", or "robots".
Google's famous search engine spider, GoogleBot, uses links on web pages as a sort of freeway. It travels from site to site by following links. When Google finds a new web page, Google will "crawl" the code on the page and transport it back to its datacenter. Google's "FreshBot" may visit "indexed websites" everyday in order to keep the index fresh. How often this is done varies wildly, is often speculated, and varies from site to site.


Google's database maintain billions of pages. They use a proprietary formula (or alogorithm) to "score" the relevancy of websites for each search query. The highest ranking, or "most relevant" websites for a specific query are listed first in the search results.


Some other factors that seem to be major contributing factors in the algorithm of Google and other major search enignes include:

• Keyword-rich, visible, on-page content in the form of paragraphs of complete sentences (not keyword after keyword separated by commas. This should be informative, descriptive text using words pertaining to your business.)
• Keywords in the title tag
• Keywords in the description tag
• The number of web pages out on the Web that are linking to your site
• The quality of the web pages out on the Web that are linking to your site
• The number of links on a page
• The keyword density of any particular section of text