Google Confirms: Keyword and Description Meta Tag No Effect in Search Rankings
Matt Cutt's confirms , Google doesn't use either the keyword or description tag in ranking websites.
Matt Cutt's gives the following answers:
1. "Our web search (the well-known search at Google.com that hundreds of millions of people use each day) disregards keyword metatags completely. They simply don't have any effect in our search ranking at present."
2. "Even though we sometimes use the description meta tag for the snippets we show, we still don't use the description meta tag in our ranking."