It is about two years that I have been studying copywriting, SEO, SEM, HTML/CSS, usability, accessibility and all that and I noticed a couple of interesting things.
The learning process
As it always happens when learning something, some things evolved and some things remained constant. A lot of information (articles, tips on forums, blog posts, etc) illuminate a certain aspect of website optimization and you either become more confident in your current knowledge or update it with the new information.