The best way to deal with trolls varies by type. To deal with the professor and critic, ignoring their rants goes a long way. They may get angrier at first, but the lack of an audience will drive them to more easily riled up communities, soon. Screamers should be gagged somehow, and are usually easy to pick out by their caps lock and swears-to-normal-words ratio.
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From the Upcoming ueue, submitted by emkay.
The example commenters given in this article are unkowingly annoying , whereas real trolls are knowingly trying to annoy or create a scenario for the lulz, ie - they sock-puppet a hot button opinion to get peoples attention and then actively try to heat it (and responents) up.