Please note, if you are in a Google for Education district, this feature might not have hit your domain yet. But it is active in your personal Google account. Here is a quick run down on how it works.
To access the feature, click on the drop down next to present and select 'Presenter view.'
Next, click on 'Start new.'
When your participants go to the provided URL, they are allowed to ask a question and vote on other people's questions. Each time a question gets a 'thumbs up' it moves up the list to be ranked higher, while a 'thumbs down' moves the question farther down the list. This is a great feature for when the presenter is only able to answer a certain number of questions. This ensures that the top ranking questions are asked first.
I love this new feature, as it opens the door to allow everyone in the room a voice to ask questions. Best part is that you don't have to switch back and forth from one tool to another. Thanks, Google!