I have searched a while here on meta but wondered why I can't find an answer. I would like to know why it is not allowed to link to phpfiddle in an answer on Stack Overflow.
I could imagine that it isn't allowed because the elementary part of the answer should be on Stack Overflow and not on an external, maybe unreliable, resource. But sometimes it is really useful if the whole code is just to much to post or will divert from the answer itself, and is not so important but additionally nice to have.
Also I think I remember that links to other sites like phpfiddle (e.g. codepad, jsfiddle or sqlfiddle) are allowed.