At our conference last week, we used Sli.do instead of a more traditional Q&A session after each panel. Our hope was to encourage a more active and engaging dialogue between the audience and panelists.
It was a huge success.
The audience submitted questions via Sli.do on their phones/laptops, and the stream of questions was projected onto a screen for the speakers to see in real-time. The audience could upvote their favorite questions, which would then make their way to the top of the stream as they garnered more likes.