Great post. It's nothing most of us don't know, but its nice to see everything in an easy to read list. I personally think everyone's belief on the SEO keyword density is wrong. If you are using a keyword about something, and you mention it in every sentence, then that would be bad. But if you REALLY need to mention it, and there are no synonyms for the product/service/whatever, it can be annoying and difficult to only use it a set number of times. As long as the text is natural, keyword density should never really be an issue. I have had to write content for several clients that only want me to use a VERY specific word just a few times. It makes the final product look weird in the end.