N ow that you've got your web page built, you've found a host and uploaded your files, and you've put the finishing touches on the website, you may want to let the world know about your site. A search engine is a program, often on the Internet itself, which searches for words that the user gives it. The search engine then looks within a database for records that include those keywords. After finding a number of sites with these keywords, the search program will then apply an algorithm or a mathematical formula, to rank the pages.
Different algorithms are the essential difference between search engines.
Many sites use the Open Directory Project for their database, but you will get widely different results depending on how the site weights different factors. The results page is then displayed with some or all of the records found and usually includes links to the locations of those records. The most common way that search engines acquire their list of keywords is from submissions. Some sites provide separate boxes for you to enter your keywords. Other search engines use automated software called robots or spiders to search text and codes on web pages to store as keywords in their databases.