This is probably relevant if you have a blog or run a webzine of some sort. It’ll be much more abstract if you are a commenter, and can’t relate concretely to weirdo creeps who persistently spam your comments and contact you via email. In relation to bloggingheads.tv my own two primary complaints from my experience on that web-show:
1) A group of commenters, lead by one particular commenter, persistently verbally abused me as a racist repeatedly even if I was talking about something totally unrelated to race (the commenters admitted that their goal was make sure that I was not invited to the show again through the campaign of harassment). Of course most of these individuals were anonymous. I told the producer that I wasn’t excited about this in relation to my future possible appearances, and he admitted that they were looking into correcting these issues.
2) The commenters are not, in my opinion, as smart as Bob Wright thinks they are. One regular commenter would offer opinions on evolution based on what Stephen Jay Gould write. This a problem for anyone whose bread & butter is evolution (I’m sure the commenter is not knowledgeable enough to know that …