Google seems to be taking its productivity suite quite seriously. Following last month's revamp of their Docs service, Google Slides has received a subtle but substantial update.
By sharing a link at the beginning of your presentation, you can let attendees post their questions on a public page. So, you'll have a live feed of all the questions and can reply to them at any point.
This feature is aimed to encourage interaction during presentations between the crowd and presenter by helping even the shyest pose questions without having to stand in public and feel awkward.