If you do something decisive about internet trolling, people will declare anything they don’t want to be exposed to ‘trolling’. This already happens.
Metafilter had an interesting approach, where they started charging a small, one-time fee for participation. That discouraged anyone from spamming accounts: anyone troll-y would find it very costly to continue to participate. (Just to clarify, ILP won’t ever do this, but if we’re talking about strategies it’s one that’s proven effective for certain purposes).
Jeff Atwood has also come up with some context-specific solutions. Stackoverflow and related sites use a reputation system to effectively eliminate trolling, but it only works in the context of a question-and-answer site, not a forum. The Discourse forum software tries to use some of the same ideas, but also attempts to use less mechanical responses, seemingly on the idea that most trolls aren’t mean-spirited, just bad communicators (e.g. a pop-up prompt when posting that reminds the user of what it means to be civil and what good discussion looks like). Atwood’s a bit of a utopian, but I’m not sure that he’s wrong. Discourse also uses a kind of crowd-sourcing of the ignore function, where threads are automatically filtered to hide the troll-iest comments, so there’s more realist solutions in there too.
Personally, I think trolling is much less of a problem than most people’s complaining suggests. As Uccisore notes, people label participation they don’t like ‘trolling’, so one person’s thoughtful engagement is another person’s trolling. Sincerity is difficult to convey on the web, and trying to prevent anyone from complaining of trolling means having an internet where ideas are never discussed in depth, and hard conversations are never had.
So, perhaps one response to the question in the OP is: it’s not a given that we need to prevent internet trolling?
As with all communication problems, the best thing you can do is give the term a very precise, concrete definition. After that, things take care of themselves.
I agree. I often return to the saying, “A question well asked is half answered.”
Many are labelled trolls that aren’t, so I’m far more concerned with Internet bullying and bullying in general, but real trolling, flaming, hounding and baiting is very obvious and is easily dealt with… usually to the uproar of the accused.