In that interview he specifically states that he tried lots of different approaches for commenting / regulation / non regulation etc.
EDIT: The most community involvement I get is when i give something away. The The regulars and base community utilize the forums and self moderate, though i need to regularly post content for them to discuss.
I've been trying to dig up as much as I can on Metafilter precisely because Matt has had 12 years to try out various moderation/management ideas.
If you have the time, I would very much like to hear more about how you manage your community.
And very true that there isn't much research here. The bibliography I did for CFP2008 has links to a couple of great research papers by Susan Herring from about 10 years ago but there's not a lot since then -- http://cfp.wikia.com/wiki/Dealing_with_hate_speech%2C_flamin...
As for scientific research: That's really quite hard to do when dealing with people stuff. (I participated in some psych/social research that was laughably badly flawed.) I did some verification of my own ideas for my own edification while very ill, largely housebound and online a great deal. I would basically predict (to myself only) what was going to happen and then watch and see if that actually happened, then intercede at some point and see what happened. My predictions were accurate enough that I concluded I wasn't imagining things and my judgement was fairly good. But there is no documentation of any of that. <shrug>
Matt, Metafilter's founder, gave a talk on community moderation at this year's SXSWi http://lanyrd.com/2011/sxsw/scrdr/ . To sum it up: good moderation = moderators and powerful troubleshooting/profiling/stats tools.
Unfortunately I haven't found much about community growth and innovation, but I've just started my research. I've been thinking about setting up a blog/wiki on this topic. Anyone interested in this?