I think it would help in many ways if discussion was immediately taken out of the speaking rooms and into another informal venue. That provides room for more talks since speeches and Q&A can then be done in parallel rather than following speeches waiting for Q&A to conclude. Imagine the presenter leaving the stage and followed out to a communal Q&A venue by those with questions.

One risk though is that anyone who moves out into an open Q&A follow-up misses at least part of the next presentation. However, that can also be solved by allowing for offline Q&A that is subsequently published out to the community later or, better yet, fed dynamically using microblogging, SMS, et al.

EDIT: to build on this...

I believe we need formal themes for talk tracks. I noticed Quim Thanked that suggestion when I recently made it so that's encouraging to me. In conjunction, I see value in adding more microblogging tags besides just #maesum... such as track theme tags (eg #GPS, et al). This can help direct people to relevant info.

EDIT 2: I see value in brainstorming on theme tags in the time before the next event (not necessarily summit) and then creating a general badge template showing how those tags would be incorporated into future schedules. I will facilitate this effort.