Great article, but what makes me wonder is the fact that the css validator on w3c.org found 191 mistakes on the actual page of your articel.
http://jigsaw.w3.org/css-validator/validator?uri=http%3A%2F%2F24ways.org%2F2007%2Fdiagnostic-styling&profile=css21&usermedium=all&warning=1&lang=en