Google Webmaster Central - keyword meta tag not used by Google
On September 21, 2009, the Google Webmaster Central blog answered many questions when they let the world know how they view and use the keyword meta tag. This is important because hundreds of thousands of people use those meta tags and without Google using them, soon nobody will.
Recently we received some questions about how Google uses (or more accurately, doesn't use) the "keywords" meta tag in ranking web search results.
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.