.
It might be just my preference, but I always added this kind of functionality using macros in MoinMoin -- sure, it's a little more awkaward to type <<<Link Page|Text|Extension|Extension>>>, but you have a generic mechanism for extending that's guaranteed to not collide with anything.
If you extend the links, then soon you will have to extend tables (to allow styling them), headings, blocks of preformatted text (for syntax coloring), etc. -- and what was a well-known, standard markup becomes some complicated replacement for HTML.
-- RadomirDopieralski, 2007-02-26
I agree that if a Wiki has such a functionality, it may be used as an alternative. At least for rare and special kind of links, like with pop-up-descriptions or window targets. However, I and I believe many are really waiting for links to become semantic, I think placing semantic web info there would soon mean: just forget that you had any old-style markup.
I think the proposal to alert developers that in future creole there may be more than one "|", which their parsers should ignore is easily done, and does not cost.