One of the things I’ve found confusing about these new structural tags is the difference between a section and an article and when to use each. The answer seems to be a matter of interpretation and in some places the tags seem interchangeable.
The two tags are similar. The difference is that an article is self-contained. It can stand on it’s own. A section isn’t. You can have multiple sections inside an article and you can have multiple articles inside a section. You can nest sections within sections and articles within articles.
Ultimately you have to decide which is the most semantically appropriate for a given situation and I imagine as html5 falls into greater use we’ll see debates about the “right” way to use each along with a lot of meaningless arguing with anyone who doesn’t agree with your “right” way.
Note: I’ll have more to say about these 2 elements when we dive into some real code next week. Understanding their definitions is easy. Trying to decide when to use which in a document turns out to be a lot less easy.