A long time ago (in technology terms), in an academia very close to us, there were stories of professors who suspended their MOOCs, or decided rant in the class forums and ultimately to walk away because the MOOC wasn't what they expected, and we all (probably) rolled our collective eyes. OK, maybe we didn't all roll our collective eyes, but I remember thinking that the "participate or get the heck out" and "read the fine textbook" were really incompatible with the MOOC framework. Initially I was somewhat anti-lurker. I'm not saying I am pro-lurker now, it's just that I don't think that lurkers pose tragedy of the commons issues, so just let them be. They don't detract from people who want to learn and experiment. To me, at the time, it seemed like an instructor who wanted to do what many have done in the past. Take a face to face class, and translate it, almost one for one, to online without really thinking about the affordances.