If some audience members are present in person and others are connected via a video conferencing link, they can all vote at the same time using Quizzbox.
You can ask questions and display results for the whole audience in real time.
For in-person participants you have two options: they can vote either with the wireless voting handset or via the web app on their smartphone/tablet/PC.
Online participants have to use the web app.
Questions and results that are projected onto a screen at the in-person event can be displayed to the video conferencing participants via screen sharing.