Most search engines use this description on their result pages. It appears under the page title and gives users an overview of what the page is about. Pages without this tag have the first few lines of the page displayed. Some search engines use the first 150 characters of a meta description - some use as many as 400 characters. 2.4 All pages should contain keywords relating to the content of the page of no more than 200 characters.
Search engines use the meta keywords field to find pages relevant to the enquiry made by the user.
A page without keywords will appear much further down a listing than a page with keywords regardless of the content of the page. Older browsers, PDA, Windows CE and WAP enabled devices may not display the images, but will display the alt text. Users may have opted not to display images on their browser and will rely on the alt text for navigation. The use of frames is not permitted. The use of frames increases download times and often prevents pages being indexed by search engines.