Meta Tags are information inserted into the "head" area of your web pages. Other than the title tag (explained below), information in the head area of your web pages is not seen by those viewing your pages in browsers. Instead, meta information in this area is used to communicate information that a human visitor may not be concerned with. Meta tags, for example, can tell a browser what "character set" to use or whether a web page has self-rated itself in terms of adult content.
Let's see two common types of meta tags, then we'll discuss exactly how they are used in more depth:
In the example above, you can see the beginning of the page's "head" area as noted by the HEAD tag -- it ends at the portion shown as /HEAD.
Meta tags go in between the "opening" and "closing" HEAD tags. Shown in the example is a TITLE tag, then a META DESCRIPTION tag, then a META KEYWORDS tag.
For further information about the usage of Meta Tags, please refer to URL as given below:
http://searchenginewatch.com/webmasters/article.php/2167931