[whatwg] strong and em difference not clear

[Edward O'Connor]

> The HTML 5 spec doesn't give clear guidance on the choice between
> strong and em tags.

The spec distinguishes between importance (<strong>) and emphasis
(<em>) like so:

"The placement of emphasis changes the meaning of the sentence. The
element thus forms an integral part of the content."

and

"Changing the importance of a piece of text with the strong element
does not change the meaning of the sentence."

So, basically, putting <em> around different words in a sentence
changes the sentence's meaning, whereas moving <strong> around in the
same way doesn't alter the meaning of the text.

Do you think that's sufficiently clear? If not, do you have a
suggestion for how to express this difference better in the spec?