“Backchannel communication is a secondary conversation that takes place at the same time as a conference session, lecture, or instructor-led learning activity. This might involve students using a chat tool or Twitter to discuss a lecture as it is happening, and these background conversations are increasingly being brought into the foreground of lecture interaction. Digital technologies allow background discussions—which have always been a component of classes, conferences, and presentations—to be brought out of the shadows and, perhaps, incorporated as a formal part of learning activities. Instructors and presenters alike should be aware of this dynamic and the opportunity it presents to add another dimension to learning”.
Source: 7 Things You Should Know About Virtual Worlds