URLs with underscores

[Aaron Swartz]

>> Interestingly, whenever I've explained Markdown-like syntax to a

>> layperson, they don't understand why _this_ is italicised and not

>> underlined.

> 

> My explanation for that would be that underlining should never be

> used for anything other than hyperlinks.


My copy of Bringhurst is in storage, but this was true even before
hyperlinks were invented. So just as something underlined when
handwritten would be typeset as italics, something underlined in
Markdown will be HTMLized into italics.