That's a nice site. Having seen what you can do with live webcams, e.g. livejasmin (NSFW), I was thinking a similar model could work for language learning. The teachers could be paid. They wouldn't be contracted and they'd be minimally screened, but they'd accumulate popularity. Maybe this could be combined with the readlang model so that you could learn by reading a text together with a teacher. I think it's evident that learning from an actual person, especially one you can hear and practice with, is the most productive way of acquiring a language.