YouTube is testing out a new feature called "Video Questions Editor Beta". They describe the feature as a way for "multiple questions to be displayed on top of your video during playback that a viewer can answer."
TechCrunch describes thusly:
It's pretty straightforward—you just enter the question you want to ask, the point in the video when it should appear, and the answers that a viewer can choose from. You can also identify one of the answers as the correct one, and offer a hint if the viewers guess incorrectly. Afterwards, you can view a summary of the answers on your analytics page.