Example:
<meta name="description" content="more about meta description tags">

"Meta name description" has not much of a meaning anymore when embedded in the sub-pages of the web site but is still required and effective on the home page of the web site. We implement this tag on all pages that are registered and submitted to search engines and directories because some of them still display this tag when search results are shown and draw their information about the page from this tag.

In fact the meta tag description tag was used excessively and is still used to spam search engines. It should be a short summary of the content of a page. Due to the major spamming the 3 most popular search engines are scanning the content and build their own description of the web page saved in their database.
The keywords in the content text, alt tags and the descriptive links are playing now the major role.