Keywords is important, because the search engines identify the site through the meta tags. Meta title Meta Description Meta Keywords & Some of the meta robots.
Keywords are which your site will be appearing in google search results & are important but the keyword meta tag is no more of any use only title & description are useful now.
You should mention that in meta tags. as Google is paying less importance to them but others has not stopped the same
the first thing that you should learn, is how to search and pick your keywords, this is a crucial step, most newbies optimize their websites for the wrong keywords and only realize it 1 year later (when they find out that their keywords are either too competitive or worthless from a traffic perspective)
Keywords tell the actual identity of your website, means exactly on which theme(s) your website is based.
Google doesn't prefer meta keywords but there are many search engines who prefer meta keywords like yahoo and msn.. and many more...so that will be better to put meta keywords...
hi keyword is must due to your link affilated from keywords. if you submit category then ignore the keywords thanks
Keyword meta tag is crucial part of on page seo, which that in html tag where every search engine support to html, so keyword meta tag help in serp.
If not for google, you may want to include it for completeness sake, and for bing and yahoo sake. It also gets important because when people bookmark your site, it goes into indexed keywords .