Here’s short post on SEO meta tags. For the majority of search engines the meta tags have zero relevance to ranking a page in the search engine algorithm. It hasn’t always been like that in the past the main ranking factor was the meta tags, like any thing that can be humanly changed we had the years of the meta tag stuffing where keywords would be placed in the description and keyword tag area often not relevant to what’s on the page. This would lead to higher ranking but made for a crap user experience with pages returned that were not relevant to what the person was searching for. Today it’s all about relevancy and user intention.
So should you use the SEO Meta TagsYes you should, let me explain why. The keyword meta tag is all obsolete for the search engines. There is a but, Some social bookmarking sites read the keyword tag and use it to auto generate tags for bookmarking and sharing. This will save any user bookmarking the page time and effort. Thus making the process of bookmarking more striate forward.
The description tag , although this tag is not used for the ranking of pages this text is displayed under the page title in the search engine results page. This gives you opportunity to write attractive and enticing copy to increase your click through rates
Remember to choose the keywords as if your were tagging the document .
Note from Google on the Keywords meta tag
Recently we received some questions about how Google uses (or more accurately, doesn’t use) the “keywords” meta tag in ranking web search results. Suppose you have two website owners, Alice and Bob. Alice runs a company called AliceCo and Bob runs BobCo. One day while looking at Bob’s site, Alice notices that Bob has copied some of the words that she uses in her “keywords” meta tag. Even more interesting, Bob has added the words “AliceCo” to his “keywords” meta tag. Should Alice be concerned?
At least for Google’s web search results currently (September 2009), the answer is no. Google doesn’t use the “keywords” meta tag in our web search ranking. This video explains more, or see the questions below.
Complete article http://webmojo.co.uk/blog/seo-meta-tags/