For example the code below will hide the contents of someone’s messages (at least with IE7). If you want to see the contents (and possibly vote on it) you can still drill down to the actual node. To use this put it in the "On-Site CSS Markup" section of your Display Settings. Obviosuly replace <userid> with the userid of the troll.

tr.pmnote-<userid> { display: none; } /* Ignore <userid> */
[download]

I had some misgivings about this as it felt like censorship. But I think the ability to drill down is a nice compromise when dealing with users who continue to exhibit crude behavior.

I’d like to thank Fletch, perrin, and several Monks who were in the chatterbox a couple months back for the code snippet and thank the Monks in the chatterbox today for giving me advice, especially jZed.

Merry Christmas everyone!!

Update 2008-04-16: I want to draw attention to tye's excellent post about the difference beteween a flamer and a troll and why you should always ignore the troll.

Update 2011-07-20: Some of you may find the suggestions in Blocking users usefull as well, such as the ones in this post by MidLifeXis.