Boardthing

Boardthing is super simple and fast board with digital sticky notes. I use it all the time during retrospective meetings, I map user journeys there or use it for a quick brainstorm meeting with the team or even just with myself. It is free and anyone can join it as a guest - no need to register. I know about other similar tools (like Mural or Realtimeboard) but they are great for more complex work. Boardthing is awesome because it is SUPER simple and totally free.