A very good article and it describes why a lot of pilots I fly with say they don't bother looking at Pprune. Of all the different forums it seems to me that the two Australian centered forums are the worst.
I noticed at the bottom of the article there is a comment from someone posting a link to another aviation based bulletin board. If you want to see a prime example of what the article is referring to then click on the link. The site is used to harass and bully anyone who doesn't agree with their point of view even if people post on Pprune or Ben Sandilands blog. There is one individual who will post the most vile of comments if he/she thinks they know your identity.
Of course a lot of teenagers would know that the Internet is the cowards preferred method of harassment and bullying.