Miro is an online whiteboard where teams can collaborate virtually to present ideas, create mind maps for brainstorming, workflows and strategic planning. It comes some built-in templates for many different kind of activities (timelines, ice brakers, meetings, and many diagrams). One of the most interesting feature is the infinite canvas on which you can work, designed in a vectoral system which allow the user to zoom in and out and move from one side of the canvas to the other. Seemingly to google docs, Miro let the uses visualise the mouse/pointer of all the collaborator working at the same time.
MIRO Presentation: https://www.youtube.com/watch?v=5sPM5dmudHk
NB: With the free version of Miro it is possible to use only 3 boards.