Big quesion still lingering: do I need to measure learning or learner participation? In an ideal world, the former. But there are probably too many variables to do this. Therefore we have to assume that, based on the literature/theory, increased participation leads to increased learning - as long as that participation is ACTIVE. And from there, we measure participation.

I'm thinking at present that the best research method to do this will be a combination of direct observation and structured interviews (perhaps an attitude scale). Direct observation seems like the most logical method of gauging the extent of leaner participation, via blog, wiki and synchronous communication. Interviews appear a useful way of ascertaining a valuable insight into learners' own experiences, which could supplement data gathered in direct observation - and after all this is very much concerned with their own experience. ...or an unnecessary extra??