In the pub after presenting on HTML5 at London Geek Night last week, a bloke (Andy?) gave the best description I’ve heard yet of HTML <article>.
Don’t think of article as a newpaper article. Think of it like article of clothing: any discrete item.
It’s not just about newspapers or blogs. So, on amazon, a single product on a product listing page would be an <article>. An individual email in a web-based email app would be an <article> Individual tweets on a twitter client would be <article>.