Major Best Search Engine - Each search engine has its own formula for indexing pages; some index the whole site, while others index only the main page. Its similar to origination of search engines that started with different thoughts. Some search engines work by automatically searching the contents of other systems and creating a database of the results. Whereas other contains only material manually approved for inclusion in a database, and some combine the two approaches. For example - AllTheWeb provides both comprehensive coverage of the web and outstanding relevancy - AOL Search provides users with editorial listings from Google's crawler-based index.