Blogging - good intentions

Hey, Blogger just did its design change thing! That's what I get for not logging on for a few days. I'm just at the start of doing three courses online simultaneously (and all asynchronous)  and I'm letting myself off the hook for most other things for the next 42 days.  The eduMOOC research study group is having a discussion about lurkers/observers/non-active participants/frivolous learners who don't have any presence in the course- whatever you call them.  It seems like if a MOOC is "do as much as you'd like", then that's what some people do. They may not do much that's visible to the other participants.  If you go to the trouble to organize a MOOC, how many active participants are "enough"?  Can you be happy if  only 20 or 30 people are really active?  100 people? I'm not sure what MOOC organizers think about that.  What has to happen to make MOOC organizers think that there efforts are totally worth it?