Since my best experience on Wikipedia was because someone plopped a WikiProject box on my user page (and invited me to remove it if I didn't want it, or join in if I appreciated it), I'm a huge fan of WikiProjects. I probably wouldn't have made the transition from new user to frequent user without a WikiProject. It's easy to feel lost in a huge city. But if you know the people in your neighborhood, or even just in your building, you have that support. You have people who can help you learn the ropes, settle disputes, discuss standards, help you with articles, and even give you a pat on the back now and then.
The problem is what you said, where you get into group wars. I can't say I've had too many bad experiences when WikiProjects collide, because usually they care a common commitment to basic premises like verify things and don't push a point of view. (POV problems are sometimes challenging, at least projects agree in principal to be neutral.) The problem is with less formal groups. Groups who pour in from off-wiki like a website or email list. Or groups without any headquarters who kind of track each other's contributions and maybe send the occasional email or user page message. These groups are not organized around improving content, but around pushing an agenda. Formal WikiProjects are usually trying to reach a consensus. But the informal groups are trying to win a debate -- and once they realize that Wikipedia does not have "winners", they dedicate themselves to filibustering the debate, making Wikipedia a more hostile and unproductive place.
A lot of this is leading us back to a good idea: social features. But it also leads us back to the hostility problem. Even with the primitive social features that Wikipedia already has, it's possible to coordinate drama and battles. We need to reconcile the contradictory goals of trying to make it easier to coordinate and help one another, while simultaneously making it harder for people to form gangs and mobs. That means having rules and guidelines where good coordination is allowed and promoted, but bad coordination is put to an end -- without sending the bad apples to pursue their crusade "underground".
This is a tough challenge. But if we pull it off, it will improve community health exponentially. I think we've found the heart of our challenge.
Ah, it's gratifying to hear that about Wikiprojects. I personally have had no involvement with them apart from sensing their presence from the boxes you see on talk pages. It's good to hear that at least one of them is doing some kind of outreach by placing boxes on user pages. Perhaps we could consider some way of making it easier for Wikiprojects to issue some kind of invite.
I have also seen FloNight suggesting elsewhere that we build on what is already on Wikimedia, which would make Wikiprojects a good target for recommendations.
All that said, I keep having to remind myself every other day "this is not just about the Wikipedias"... so I don't know whether WikiProject cultures exist on other Wikimedia projects. Similarly, FloNight has made me aware that there's already quite a culture of "contests" on en:Wikipedia which might make a good foundation for the "rewarding editors" theme, but whether contests exist on other projects I don't know either.
I'll write myself a To Do note to go around all the English projects and ask on the various Village Pumps and see if I can find out. I have been feeling a bit stuck as to what to do if I'm feeling a bit too tired to read the last 48 hours, so that will give me a meaningful task for tomorrow.
Yeah, there's so much to read. Sometimes you have to take a break from reading dense reports, and sometimes it's good to just google around, or try to write down some ideas yourself. I'm sure that we can expand our ideas so they're relevant to all the Wikimedia projects, although I think our big community health challenge is really about figuring out why growth has stabilized and how to fix that.
I've spent a lot of time trying to find data that helps us drill down into the problem. But I'm almost positive that it's going to end up reinforcing the broad solutions you're working on. I'm hoping to shift my effort from data gathering to discussing the actual problems very soon.