A Web page is a document. A component, whether it’s part of a blog template, a news site, a marketing stats dashboard or a sign-up form, is a part of a document. Documents have structure. On the Web, that’s not just about the visuals or the architecture provided by your framework, it’s about choosing semantically correct elements that make sure that your Web page, component, whatever, is correctly structurally formatted. Headings should be headings, lists should be lists, buttons should be buttons and tables should be tables. You can style them (pretty much) however you like – a heading doesn’t have to be big and bold with a bottom margin. That’s up to you, but it should definitely be a heading and I’ll fight you if you make it a div.
This is such a great piece. If you build anything for the web or are at least interested in doing so, read this. Then consider learning some HTML. If you’ve never touched it before, I think you’d be surprised at how quickly it can be picked up.