So far - Google searches in my web site come from my pages titles, old content -especially the H(x) titles, but none of the keywords brought me traffics according to Google Analytics. Many web sites don't bother including keywords. Are they still important?
It seems to me you are referring to the meta-keywords tag. Most people when speaking about "keywords" would actually mean the words that a user will type in a search engine when is searching for something. And yes, those keywords you should try to optimize for.
Damn...keywords is the main tool that is used while search in SE's. So why should one neglect them ? Its right that meta-keywords has lost its prominence.
Keywords are very important but even if you dont include in your meta tags, some SEs can still pick from your page content. Keywords are essentialy what people use to get to your site through SEs so you need to pay attention to it.