The latest in the excellent Educause 7 Things You Should Know About… series is Backchannel Communication which is described as:
secondary electronic conversation that takes place at the same time as a conference session, lecture, or instructor-led learning activity
The backchannel at a live ‘event’ is usually informal and takes place on tools such as Twitter with the audience sharing comments, questions and links with each other while continuing to follow the the formal presentation. The 7 Things guide notes that increasingly the backchannel is being brought to the fore as speakers & lecturers positively encourage the audience to participate and then respond to questions posted. In some cases the communication is being displayed on screens within the lecture theatre.
Some institutions in the States have gone as far to create their own backchannel tools, for example Hotseat from Purdue University & the free to use Live Question Tool developed by the Harvard University’s Berkman Center for Internet & Society.
There are a number of opportunities & challenges raised by the backchannel and I recommend reading the 7 Things guide in full: 7 Things You Should Know About Backchannel Communication (PDF)