In that light, it was interesting to read a post by David Crotty (describing thoughts from Mark Cuban) which argues that participation in and the shelf-life of online discussions are inversely related. Our observations, ranging from The Apprentice to ALT-C, certainly seem to support the hypothesis. The VLE is no longer a contact sport. Rather, it has become the box through which a multiplex of channels make it onto the screens of the punters (or don't, as the case may be).
It's now perfectly possible for me to embed a Wave in Blackboard, although in reality, I'd be far more likely to embed some of the functionality of Blackboard (maybe the Gradebook) in a Wave. The conversations around learning are becoming ever more fragmented, and as they do so, participation becomes ever harder to measure.