"Mentimeter allows you to use mobile phones or tablets to vote on any question you specify. Our vision is to improve the meeting between a presenter and an audience."
"A real-time group brainstorming and decision making app. Dotstorming takes the process of dot voting online to allow groups of people to collaborate on a topic."
While people attend presentations, panels, and lectures to learn something from the people at the front of the room, there's a lot of potential for creating spaces where audience members can interact with each other and the people presenting. backchan.nl does this by providing a web-based interface for audience members to identify themselves, post questions, and vote on other people's questions.