Local NUS (National University of Singapore) students have come up with some innovation to address the problem of Q&A during seminar or etc. They created Pigeonhole Live, a system that allows you to post a question and intelligently.
I guess many people must have problem to come up to a microphone to ask a question during a seminar or etc. Another problem is getting your questions answered. Some conference or seminar might have provided paper for you to post a question and the speaker will randomly pick the questions to answer. Sometimes, they missed your question although it might be an interesting one.
These NUS students felt these frustrations and came up with intelligent solution. At Pigeonhole live, you need not have a account. You will only need to input a conference ID to ask question. These questions will be automatically appear to the speakers.
If you are those that do not want to post a question. You can also participate by voting the questions posted by others. In this way, the speakers will know which are the questions that are of high interest for them to answer.
No private information are collected. You can post anonymously. I think this is really a great idea. Pigeonhole Live is now in Private Beta. If you are interested, you can leave your email at their site.
http://www.pigeonhole.sg
Here is a short video on how it works