I’ve long disabled HTML in comments, basically to help my readers avoid accidentally clicking through on comment spam. But now that I seem to be managing the comment spam well enough, there’s no reason not to let real live human commenters use HTML when they want. So:
Comment HTML for everyone! (except spammers, of course.)
Naturally, I ask everyone who chooses to adorn their comments with links and html to show some basic common sense and courtesy to me and other commenters, and if I think someone’s use of HTML in comments is egregiously bad, I go in and snip it out (though, as with general editing of comments, I can’t see why I would do that very often). The good news here is that I think most you already have common sense, so this entire paragraph is redundant.
There you have it.