Comic book artist and web forum owner John Byrne has declared his forum to be a "Wikipedia-Free Zone" and banned all links to Wikipedia regardless of content or context:
http://www.byrnerobotics.com/forum/forum_posts.asp?TID=16456&PN=1&to... osts=105
It seems his grievance against Wikipedia is that he was unable to bully it into suppressing all mention of controversies and criticisms of him in his article, and rebuffed his Daniel-Brandt-ish demand that the John Byrne article be either deleted or permanently locked.