"Ostracize" does not work well online. You don't get direct feedback on how many people read what. (Even the downvotes are evidence that someone did read the comment, and expended some of their energy to downvote it -- which supposedly is part of what the trolls want.)
There is no online equivalent of a group turning their backs on someone in ice-cold silence. Just "not answering" is not the same thing... that happens to many normal comments too.
As far as I can tell Will Newsome hangs out in Berkely with SI folks.
The recent implementation of a -5 karma penalty for replying to comments that are at -3 or below has clearly met with some disagreement and controversy. See http://lesswrong.com/r/discussion/lw/eb9/meta_karma_for_last_30_days/7aon . However, at the same time, it seems that Eliezer's observation that trolling and related problems have over time gotten worse here may be correct. It may be that this an inevitable consequence of growth, but it may be that it can be handled or reduced with some solution or set of solutions. I'm starting this discussion thread for people to propose possible solutions. To minimize anchoring bias and related problems, I'm not going to include my ideas in this header but in a comment below. People should think about the problem before reading proposed solutions (again to minimize anchoring issues).