Ever wondered, how search engines are able to generate so relevant results? Search engines run with the concept of huge databases of web sites that surfers can search by typing in some text. Google highly recommended as a first stop for those searching the web. Each search engine has its own formula for indexing pages; some index the whole site, while others index only the main page. Google's crawler-based service makes heavy use of link popularity as a primary way to rank web sites. This can be especially helpful in finding good sites in response to general searches such as "cars" and "travel," because users across the web have in essence voted for good sites by linking to them. The system works so well that Google has gained wide-spread praise for its high relevancy.