Jamboard is G Suite'sdigital whiteboard that offers a rich collaborative experience for teams and classrooms. It lets you collaborate in real time using either the Jamboard device (a 55-inch digital whiteboard that works with G Suite services), web browser or mobile app.

https://youtu.be/-RaT2sHL4aw

Advantages

• Free.
• Easily sharable.

Disadvantages

• Large amount of users may experience trouble editing the same board at once. 
• Harder to evaluate student contributions.