Forget about keyword density when it comes to
Yahoo! You should aim to get as many keywords
as possible included, but not too many that
the Yahoo! reviewer chops it short.
The Yahoo! database contains only the details
that you see on your listing, what your pages
actually contain is irrelevant.
The title of your Yahoo! listing does have
higher weight than the description, but the
Yahoo! reviewers always try to keep titles
as short as possible. If they can list only
your business name, then they'll do just that.
I'm starting to repeat stuff I've said in the
Yahoo! section, so I'll stop now.