Uhm, http://<b>perlmonks</b>.org is displayed in HTML as http://perlmonks.org, which is a valid URL. Now, it's not "clickable", but then, http://perlmonks.org isn't marked up to be "clickable" either. For that, it needs to be wrapped into an anchor, like <a href="http://perlmonks.org">http://perlmonks.org</a>. But <a href="http://perlmonks.org">http://<b>perlmonks</b>.org</a> is valid HTML. And, in most browsers, "clickable": http://perlmonks.org.

So, where exactly is your problem?