This is more of an article "stub" than anything since some of the planned content for this site on Search Engine Optimization (SEO) has been delayed. But a quick FYI post seemed appropriate.
I've noticed a fair amount of content on the internet in various places - not all of which is "old" - urging website owners to pay attention to including meta keywords in their site's pages. But here's the thing: you would probably be wasting your time.
Unless you are targeting a smaller or more obscure search engine that does use meta keywords, there is little point in including such in the head tag of your website. Google doesn't use it. Some mentioned that Yahoo still does so I did a test the other day. Conclusion: Yahoo doesn't use meta keywords either.