Google's Webmaster Central Blog recently posted a useful guide to using the Description metatag. The tips are designed to help websites display a more effective 'snippet' of content within the search results list, which may come from this metatag text, or from the page content.

The main tips are to revise the Description tag on each page as much as possible, to reflect the page content and to provide the searcher with accurate and relevant information which, ultimately from the website marketer's perspective, will make the user click on the link into the site to find out more.