Garbage - In my opinion, poor quality Whiteboard paint, do not buy
Witeboard - A real-time whiteboard for your team. No signups required.
Ziteboard - Ziteboard is an zoomable online whiteboard that lets team to collaborate in real-time.
Whiteboard Fox - Simple Online Whiteboard
Idea Paint - Create a usable, interactive space on any flat surface
Stormboard - Stormboard empowers data-driven companies to turn their unstructured whiteboards into data-rich collaborative workspaces; enabling data-driven decisions and efficient processes — often eliminating the need for meetings entirely.