Well, I see your point. But what I experienced before was not 'classes' per se, e.g. one teacher and regular meetings.
What we did in the other forum was putting good, substantial language teaching notes up, regarding a specific subject, grammar, verb conjugation etc.. These would be put up as stickys which the original poster could add to. As a mod I was able to decide who should be made into stickys (the ones that were decent and comprehensible). People could then ask questions and make comments about specific lessons in the regular thread section beneath. The stickys was set to strictly reading mode, except for the person running the lessons.
Ex:
Japanese Beginners Lesson 1:
Hiragana & Katakana (this would be an explanation of the writing system in Japanese, with charts provided, and I also added soundfiles for pronunciation)
The lessons were simple and aimed to explain basic features of a specific language. There is no way to teach someone to speak a language fluently on a randomly posted forum such as this one, but there is no need to go that far. The point is to teach what you know, even if it's just the basics. I'm not fluent in Japanese, but at the time I was the most experienced out of us, and managed to teach some important basics to beginners. It would be fun to add other languages as well, as I'm sure there are a lot of people here with various mother tongues, but I would want to restrict the lesson-making to people who are able to present them properly.
These lessons and discussions are meant to exchange information; not to give someone a qualified diploma (but it might inspire them to enroll for one sometime?

)
How does that sound?
Lawliet, I see your point, but I think it would be near to impossible to try this on a single-thread basis, as the lesson-notes would be jumbled in with people's comments (which, as we all know, tend to digress.. lol) I could, however try to create an example-thread for a lesson, so that people can see how it could work (I might have to give it a few days, as I no longer have the old lessons on my comp, and I need some time to create new ones).
Good, idea; I'll put up a poll in this thread.
Thanks for the feedback
Edit: oh, someone already put up a poll. Good thinking