Troll: someone who is deliberately aggressive or disruptive in a discussion.
When the new whitehouse.gov went live many people questioned why it wasn’t open to comments and discussion. We have worked on a few projects where this is a very sensitive issue. We’d have loved the comments to have been more open, but issues of the appropriate use of language on sensitive websites could have opened them up to various problems (a subject for a much longer journal entry). That said there have been some intriguing innovations in how to handle commenting on blogs, discussed in this article on Wired.