There are many types of meta tags and each is used for a different reason. Examples of meta tags include description meta tags, which is used by search engines to display a description of a web page in their results or no cache meta tags which makes sure that the latest additions to information are included in the search displayed to the user. No cache meta tags are used to tell an internet browser not to cache a certain page. This would be used in setting parental controls where certain sites cannot be accessed on certain computers in the house or at all. Every function of a web site including its interaction with various search engines are controlled through the use of meta tags.