A couple of years ago Mark got caught up in the Wayne Crookes "Libelpalooza" and, although the case died in a B.C. courtroom, Crookes has appealed and there are many bills still to pay. You can get the more details on Mark's particular situation re his blog, but one of the worrying things about Crookes' efforts is that he has sued people (Michael Geist, specifically) for linking to a site that linked to another site that contained allegedly defamatory material.
Now that's scary.