The meta tag does not have a closing tag it is also not self-closing.
A meta tag is placed in the head of the web page and will not be displayed on the page.
Meta tags give information about the document some of which is read by the search engines.
At the moment (March 2012) non-defined meta tags are not validated by HTML5 validators. If the meta element is not defined in some cases it can be registered registration information.
Name
<meta name="" content="">
A name attribute is always paired with the content attribute. The content gives information or value for the name.
Defined Names
application-name
Represents the name of the Web application that the page represents
author
Name of one or more authors of the document
description
A statement that describes the page
The description is used by most search engines as the snippit of information that appears with their results
generator-name
Name of the software used to code the page.
Not used if page is hand coded.
keywords
Used by search engines. Keywords are not longer used by Google but are still used by other search engines