Identifying learning dialogue

I've switched to a different data source in my quest for learning analytics. I'm currently looking at interaction around the OU's online learning and technology conference this June. I have access to a lot of data around this conference, but I'm currently focusing on two elements: the Twitter stream, and the text chat that took place in Elluminate during the sessions.
The two data sources are superficially similar - short textual contributions shared online over a limited period of time and focused on similar subjects. Although they have asynchronous features, and have all been archived, they are largely synchronous communications.
I'm trying to dig into these to go beyond rich description of what happened, to find some underlying patterns that may be helpful for identifying/supporting learning in the future. I am currently focusing on / flitting between four areas: language, resources, individuals and networks.
In terms of language, I'm trying to identify patterns of speech and interaction that suggest learning may be taking place. I'm currently focusing on the patterns that Neil Mercer and his colleagues identified as characteristic of exploratory dialogue: analysis, explanations, explicit reasoning, justifications, reflection on the perspectives of others, challenges and counter-challenges. And I've narrowed the focus to learning about content, rather than to learning about the tools or learning about other people - so I'm setting aside discussions about how to make sure you can hear the speaker, or which types of biscuit are best to eat in a coffee break. I know those are all examples of learning, but I'm not looking for ways of encouraging reflection on the merits of custard creams.
This takes me on to resources - because descriptions of exploratory dialogue were developed in a face-to-face context, where the resources to hand were limited. In the context of online dialogue, maybe it is this linking out that supports exploration - or maybe it is linking out and then returning for discussion that is important - or maybe the important thing is linking out that moves the discussion to another venue (if that turns out to be the case it's going to be very difficult to research).
And maybe it's a mistake to set aside the people, because I may find that learning is associated with certain individuals. That may be because they are making interesting contributions, or because they are central nodes linking networks of people, or networks of resources, or because they are contributing think pieces elsewhere, or because they are asking interesting questions. In that case, learning about people may be key, because it's important to find and follow these people. So what marks individuals out as key? Is it because they initiated the hashtag, or is it that every conversation peters out if they are not involved, or do they mark themselves out as confident/off-the-wall by initiating conversations about virtual biscuits?
So many possibilities.