Good news @Sfi81, there are some tools for this.
If you want to plan ahead and do that in detail or just sketch around with freehand drawings you have the ultimate zoomable whiteboard at your service which works in every browser. Give it a try at https://ziteboard.com Let me know if you need help with it.
Whatever it will end up in I hope you'll get to a common understanding of communication principles and obvious signs of tasks to be dealt with. For us (team of 9) a 'relay race' worked the best so several calls had been made between who were awake and we used a shared platform to discuss, annotate and see through the order together with the client.
We're on it, so you'll have alternatives quite soon. What order would you suggest for login, like: email, twitter, fb, G+ ? What's the most painless login option for you?
I'm happy that you like it. Data: in browser and backend. The stack is custom - based on canvas famo.us and node on the server side. Is there anything else that might be of interest to you?
Thanks for the clarification. I guess this solution is capable of becoming such a platform, but need the insights of such visual people. I'm happy to discuss further what would provide real value. What do you see a defining pain-point?
Well, sure there is. Have you seen http://ziteboard.com ? Drop me a message and I'll show how real-time visual collaboration works - and yes, we're talking vectors.