The automatic marking-up when you've

The automatic marking-up when you've selected text and start typing a tag idea goes something like this: some text you want to mark up is selected.

Melissa suggests that cyberdiversity akin to biodiversity

You start typing a tag like, say, <em>. The editor says to itself, "Hmm! That started with a '<'! It must be markup!" and so realizes you don't actually want to replace that text but mark it up, and that it requires a closing tag:

Melissa suggests that <em>cyberdiversity</em> akin to biodiversity

The program would have to handle attributes, too, so if you included ' class="madeupword"' you'd get:

Melissa suggests that <em class="madeupword">cyberdiversity</em> akin to biodiversity

Anyhow, that'd be nice for editing HTML now that I do it at least daily.