#21: Floating navbars are an abomination and make your site incredibly frustrating to read on a mobile device -- especially in landscape mode. At least put an X button on that thing.
Your content is or should be the most important part. The rest of your blog should be subservient to the content.
Edit: it's a good list, though. Content > presentation, when it comes to actual reading material.
Sent from my iPhone. (Note: really android but iPhone for dramatic effect)