Just over a year ago I reported on my blog that Google had finally verified that it ignores the meta tags of pages when calculating rank. I failed to post it here so that you could all benefit. While we in the profession knew this for quite some time, and also know that none of the other search engines use them, either we often find clients being wooed by SEO salesmen.
Here is the quick breakdown, although we recommend you read the post on our blog to get the full details:
You may have noticed that QuantumCMS includes fields to allow you to add meta descriptions and meta keywords to the site. We do this for best practices. Our clients often expect them and we provide them, along with counsel that the search engines will ignore them. More importanly, we provide the ability to add even more meta tags, including custom meta tags. These are meta tags that don't affect your search placement, but may be useful for tracking and reporting in Webtrends or Google Analytics, for noting a page's expiration date/time, for identifying a language or character set shift, for telling a search engine not to index a specific page, or many other purposes. Google provides a list of example tags if you'd like to review them.
While you are here, you may want to review my post Derek Powazek on SEO as Snake Oil for more insight into SEO and SEM scamming techniques to help ensure you don't fall prey.