I've read about how keywords should represent anywhere from 3-5% of your article. Does this include meta descriptions, meta keywords, hyperlinks or does it only apply to the body of the text? Thanks in advance.
Keyword density is meaningless. Just write naturally for your human audience while ensuring your keywords are included naturally and appropriately where they'll give you the most bang for your buck.
i too don't believe in keyword density, i have said this many times before, it's useless, however i believe that your targeted keywords and related keywords should be used in the body of your pages, regardless of density of course.
Ketword density is a proporation between the total number of a keyword or keyword phrase appearing on the page and others words'. As far as google is concerned, the ideal proporation is %5-%7. According to the definition above, you can see that it's only related to the body of the text. Hope it can help you.
Wrong, wrong, wrong, wrong. Google does not have an ideal keyword density. They care more about people writing for other people rather than gaming the search engines. Some pages can get away with a "KD" as high as 15% while others get whacked like a mole (or a sportsman hanging out with Dick Cheney during a bird hunt) for having a density as little as 2%.