META tags were developed and made a HTML standard for the purpose of addressing specific information about your web page that does not affect the way your page actually looks.

Meta Tags are the "tags" that inform searches which keywords should pull up a website, and these tags are hidden from the user. 

The primary META tags that affect promotion include the "Description" and "KeyWords" tags. Also mentioned here is the "Title" HTML tag used to define the title that appears at the very top of your web browser when you visit a web page.

Unfortunately, many people are taking advantage of these tags and having tags that either have nothing to do with the site (i.e. Al Gore used MP3 as a meta tag in his campaign website) or other companies use competitor names as thier own metatags (i.e. Coke might use a 'Pepsi' meta tag).

Most major search engines no longer use meta tags when searching for pages.