Now that I've read the reasoning
(
http://en.wikipedia.org/wiki/Wikipedia:Templates_for_deletion/Log/2006_July…)...
Here's the deal. I created this ISBN template {{ISBN}} which does
nothing very exciting. It simply substitutes the text "ISBN {{{1}}}".
However, my reasoning for creating it seemed sound: to provide an
abstraction layer so users don't have to learn the rather arbitrary
syntax that Wikipedia uses to deal with ISBN codes. Instead, they can
use the same syntax they use everywhere: {{template name|argument}}.
Is this a bad idea? Personally, I find the ISBN markup extremely
arbitrary and maybe not that well thought out. We apparently only
allow pure ISBN numbers, with no hyphens, spaces or slashes, although
they are usually presented that way in other contexts. By wrappering
this syntax in standard template syntax, we would clear the way for a
future, more forgiving ISBN syntax to be implemented.
[...]
You're allowed hyphens but not slashes. Are ISBNs sometimes written with
slashes? If so, we'll add that to the character list. We have to be
fairly conservative with the regular expression when we're detecting
things in plain text. I don't think there's any need to introduce a new
"abstract" syntax before we can make that change.
-- Tim Starling