I just came across this answer, which included a note that the URL they tried to use wasn't being recognized by the markdown engine.
I tried swapping the hyphens for
%2D and suddenly the URL was recognized. When I clicked the link to confirm it worked properly, I noticed Wikipedia was performing a redirect from http://en.wikipedia.org/wiki/Model-view-controller gets redirected to http://en.wikipedia.org/wiki/Model–view–controller.
The difference is subtle, but the "proper" Wikipedia URL uses an ndash instead of a hyphen. As you can see from the links above, this is a breaking character for Markdown URLs.
I know that in this case switching with hyphens works, but should Markdown be updated to allow this character (and probably the mdash as well, for good measure - any others?) in case there are situations where it doesn't?