Google does not make use of the keyword meta tags in determining web ranking. Google has stated this publicly on several occasions, case closed!

Despite this clarity (which we do not always get from Google), webmasters and even SEO bloggers still cling to the outdated concept of keyword meta tags. And you can still find webmasters mindlessly stuffing hundreds of terms into keyword meta tags in an effort to improve rankings. It has been over ten years since that technique was good for even a mild bump in rankings.

True, some smaller search engines still employ the keywords tag in ordering search results. Notably, Bing publicly acknowledges that it still makes use of keyword meta tags in ordering search results, but warns that because of historic abuse, they'll not give keyword tags much weight. Bing's Product Manager, Duane Forrester, put it this way in a blog post, Getting it right is a nice perk for us, but it won't rock your world. Abusing meta keywords...