Keywords: This should contain a short list of keywords and terms related to your site. Generally they should be separated by a comma, but some people prefer not to use any sort of delimiter.
About Meta Tags At one point meta tags were considered a relatively important factor by search engines. AltaVista and other older search engines used them to help determine a site’s theme as well as relevance to a given term. This is no longer the case; search engines now rely on much more advanced techniques to do this. That said, meta tags still have some life left in them; they are sometimes used as the snippet of a site's content in search engine result pages by Google, and possibly other search engines. It's also possible they still have a little influence with some search engines in determining a site’s content.