Mural - MURAL is a visual collaboration workspace for modern teams.
Witeboard - A real-time whiteboard for your team. No signups required.
Sketchboard.io - Visual Remote Teamwork. Solve problems and create ideas on endless whiteboard with your teammates by sketching.
Whiteboard Fox - Simple Online Whiteboard
BeeCanvas - Realtime & Interactive Whiteboard. Collect and organize everything in one place.
Cr4yon - Simple collaborative whiteboard ideal for remote teams