[mst]

Underscores indicate emphasis, just like underlining would, but in text you usually get italics (I'd note that this is often an <em> tag so it being italics is a browser default style).

Plus underscores get used -lots- of places for italics; I've yet to see the / form in the wild.

A markup language being (as here) used for technical purposes can easily be interpreted according to geek writing conventions.

[eviks]

So the intuition for _ would be underlining! Pretty simple. Where would your intuition jump to for underlining in markdown if _ is italics?

Em is just another bad term - which of the emphasis styles do you mean?

Re popularity - so what? How does widespread bad turns into intuitive good?

Bear notes used / for italics, also Orgmode (is that geek enough for you?)

[kazinator]

> Where would your intuition jump to for underlining in markdown if _ is italics?

You have you know the fact that actual underlining had been traditionally used as a substitute for italics in hand-written and typewritten papers.

As in, in a citation, when you give a title of a book, you underline it, unless using a word processor with fonts, in which case you use italics.

Learned this in high school.

[eviks]

Did they teach you in high school the relevance of that history? Does the fact that it'd been traditionally used as a substitute mean you can't use underlining now, so it should not event exist in markup?

[kazinator]

It's pretty obvious that underlining is something that rarely appears in print. It is mainly an annotation device: something added to finished print, by hand.

When was the last time you saw underlines in a book that weren't added by a previous reader?

Underlines are bad typography that should be used sparingly, if ever.

[eviks]

It's even more obvious that we're not talking about print, but a markup language anyone can outside of book publishing. So why do you want to prevent a "previous reader" from using said annotation device for the little note he's creating/editing?

[kazinator]

Sorry, how did we get here from explaining the intuition behind _..._ denoting italics?