It seems to be against several goals of Creole. There is already
a markup similar to this proposal, less verbose, with end tags which
can be recognized easily, standard and very popular: XML. Since
Creole doesn't use single angle brackets, it would be easy to
mix both.

We're soon going to have assigned a meaning to all double
punctuation signs, so Creole won't be much more complicated
than it is now. I'd suggest to reserve {{{$$}}} for LaTeX math, {{{__}}}
for underlined, {{{--}}} for deleted text and {{{++}}}
and {{{%%}}} for future uses (all optional), and we're done.
Both {{{!!}}} and {{{??}}} are too frequent in plain text to be safe.

-- [[YvesPiguet]], 2007-Apr-2

As far as I know, XML is a general markup language, not a set of text formatting rules. You surely mean HTML or XHMTL or one of the other text-formatting SGML/XML derivatives :)

I'd say that "{{{--}}}" is also too frequent in text to use it for markup, so while it fits so fine semantically with "deleted" and visually with "strike trough", it is better avoided -- see the discussions in [[HyphenListMarkupProposal]]. You can always use things like "{{{[-foo-]}}}" of course, but we are just making a poor reimplementation of HTML and friends this way.

-- [[Radomir Dopieralski]], 2007-Apr-03

XML: yes, anything more or less based on SGML, XML or [[|SML]] would be better than underscores, and this should be left outside Creole Core.

Double hyphens: I thought the same quickly after posting, but I didn't want to hide my point with a minor edit.

-- [[YvesPiguet]], 2007-Apr-03