These are good points on dealing with trolling as an individual. Ignoring it is the best, and most often ignored, advice. It's too easy to get emotionally drawn into a trolling comment, which is why I've always liked the idea of sandboxing trolls in a way that allows them to think their comments are being accepted while eliminating them from the rest of the participants of the site.

At a higher level, though, sites and moderators of discussion have to participate in the reduction of trolling. Failure to do so dooms a community. I've left my share of communities, mailing lists, usenet message boards and the like due to it being tiring to participate in a discussion that devolves into name-calling and wasteful trolling. My favorite example was Digg about a decade ago. At some point the trolling problem got so bad that you couldn't leave a comment of any kind without encountering a land-mine. I remember the "straw that broke the camel's back" was when I spent a few minutes leaving a multi-sentence comment and had copy/pasted part of a sentence to a place where it made more sense. I had accidentally doubled an "and". I was met with "Learn fucking English, asshole!" and was like "huh?!". The guy read my entire comment and grammar trolled me over an obvious typo? I deleted my account shortly after that. I wasn't angry -- I just came to realize that the site stopped providing me any value.