The back channel actually deceased the value of the talk, people were either trying to outdue previous comments or try to read them and stopped listening to the presentaiton. Harold, your comment counteracts a key concept of learning,people can't read and listen at the same time, they have to make a choice. Maybe people are used to it (like multitasking) but the effectiveness in which they do multiple things is very poor. Did you notice the difference during the final key note given by jay cross...simply asking users to login caused the comments to cease (with one exception) So while the new toy concept may hold true, people like to be anonymous more than they lead on and it really showed that the back-channel concept had zero value. And this is a human thing, it has nothing to do with learning...prepare a class to go along the same lines and it's effectiveness will be zero. Not great when people pay 16-30k for an hour of custom elearning content creation. No ROI, means no repeat business.. On a larger note, the presenters tried to be TOO cutting edge and ended up alienating a large chunk of participats. While Jay may have blogged that 99% received value, I would argue that by the time that question was asked the audience was 1/2 so really, less than 50% of the users thought they got their money's worth, or stayed long enough to voice an opinion either way..