Their mission statement reads "Empower learners of all ages to define their voices, share their voices, and respect the diverse voices of others." That's a tall order if you ask me, but FlipGrid manages to do just that.
Flipgrid is a video discussion platform where participants respond, record, and reply to topics curated by a facilitator. Facilitators use a device to create a grid (virtual classroom), and then adds topics to the grid. After the topic has been created, the facilitator then invites participates, using a code, to access the grid using either computers or mobile devices. What's great about FlipGrid is that each grid has customizable security and privacy settings.
The good people at FlipGrid created a nice set of resources and an FAQ to help answer any additional questions. Checkout this two minute video about how to get started with FlipGrid.
Setting up an account is FREE, and more than enough to get things going in your classroom. Follow them on Twitter!