On this question I was trying to put a link in a comment. The link is en.wikipedia.org/wiki/RSA_(algorithm). But the end parentheses isn't part of the link. Is this a bug, or am I just doing something wrong?

Instead of the plain link like you used (http://en.wikipedia.org/wiki/RSA_(algorithm)), you can use the markdown version:
[RSA](http://en.wikipedia.org/wiki/RSA_(algorithm))