If I could fix this I'd be launching the next billion dollar start-up around the technology. Just about every site goes through this type of growing pain: in the beginning it's obscure and spreads by word of mouth so that all of the people who visit the site share a common ethos; then, it grows and starts to attract other people who do not share the spirit that started the site; eventually, the "new" users outnumber the old users and they begin to set the standard for the sites personality.

You can try to raise awareness and ask people to not be evil on your site, but that's almost as effective as asking the tide not to come in. There are many bitter people in the world and they outnumber the well adjusted people who would rather spend their time building up a project instead of tearing down someone else's. These trolls crave attention - the negative attention they get by aggravating people on-line - so it's really not affective to point out the problem and ask them to stop or to ask the community to gang up on them; that's what they want.

We need a solution that frustrates these people. I've seen some sites where the comments a troll posts look like they are live on the site to the troll but they are hidden from everyone else. I think this is a very effective technique because it denies the troll the attention he is seeking and it saves the rest of the site from his attacks.

But, perhaps the best response is to remember Margaret Thatcher's advice about people trying to make you angry (i.e. no one can make you angry without your permission). If you see something that's not in the spirit of hacker news, just ignore it. Don't respond; don't show it to other people; just let it die a bitter and lonely death.