Forum Moderators: open
I assume from your question that you are referring to the <meta name="keywords"> tag. Keywords (in the sense of words and phrases that your site is targetting to rank well for) certainly are necessary.
Opinion is divided on whether the keywords <meta> tag is useful any more. It probably depends on your strategy. It is still used by minor engines, so if they a part of your strategy, yes it would be a good idea to use on. If you are banking heavily on Google, then its probably a waste of bandwidth
Welcome to WebmasterWorld!
Don't miss paynt's welcome message [webmasterworld.com], nice way to start.
Keywords in plain text on visible ereas of page = 96 % yes
Keywords in meta keywords = 2 % yes
Keywords elswhere = 2 % yes
<added>OOps I forgot to mention keywords in link text from other sites pointing to yours, for another 10 % ;) </added>
[edited by: Macguru at 4:19 pm (utc) on June 13, 2002]
As has been said, some of the smaller engines do rely on the keywords tag.
In my case some of these smaller engines are very important to me as they relate to my region. Including the tags lets me rank very well in these engines for a targetted local audience.
If your focus is on the bigger global picture and you don't count these smaller engines as significant to you, you could consider leaving them out.
I certainly don't think it hurts to leave them in though.