> That’s nothing new to memorize, because you already have to know what elements are allowed in that context. E.g., even in XHTML served with an XML MIME type a

> That’s nothing new to memorize, because you already have to know what elements are allowed in that context. E.g., even in XHTML served with an XML MIME type and parsed with an XML parser, <p><p></p></p> is invalid XHTML, because <p> can’t contain <p>. I already have to know that rule when writing a webpage! Knowing that <p><p> is equivalent to <p></p><p> doesn’t require higher mental overhead. "It's no extra effort to memorize this piece of random trivia, because it's already implied by this other piece of random trivial that you already have to memorize" doesn't actually make it any better. I don't want to remember any of this stuff! And with Markdown I don't have to.