This is a fascinating and relevant article which I should have brought up a lot sooner. The guy there basically says that there are all these online communities that have been perpetuating the same patterns over and over again, and people should start paying attention to the patterns and stop being surprised when predictable outcomes appear.
There are three things to accept, and four things to design for.
First: it isn't possible to separate the social issues from the technical ones. You can't just hand somebody the keys to your forum software without also involving them in the social moderation process. You can certainly try to keep those two things distinct; you can also try to fly by jumping off a cliff.
Second: not every
user is also a
member. Somewhere in your community, there's a core group that cares more than average about the health and sustainability of your community.
Third: the core group's desires are sometimes more important than the desires of the majority. It's the basic idea of rule by the majority, limited by the rights of the minority. The core group has to be able to defend itself against the whims of the mob.
These first three basic concepts are inevitable. Even if you don't plan for them to happen, if your community is going to last, you'll find they happen to you anyway.
Four things to design for, then.
First: our accounts need to accrue weight. If I do something ridiculous and get a bad reputation for it, I shouldn't be able to just create a new account and instantly have all the privileges and powers my old account had.
Second: there needs to be a way of having "members in good standing". This is an inevitable product of interaction over time; a karma system would just make it all the more obvious. Karma probably isn't necessary, but I think it would be beneficial. (Besides, it's handy to have that record so that you can see
why a person has the reputation he has, for good OR for bad.)
Third: there should be barriers to participation. It should take work and commitment to gain the privileges afforded a member in good standing.
Fourth: you've got to find a way to deal with scale. The more people you get into a single thread, the less depth any person's able to contribute.
In conclusion: salted sunflower seeds are salty.