Chris Pratley has a great post on the way the OneNote team use the shared sessions feature that they built into their product. This is the feature that I mentioned in my post On Distributing My Office Whiteboard.
This type of seamless no-baton collaboration is firmly at the heart of my personal vision for one of the key user experiences of modeling tools, i.e. sketching. In the medium term, I believe that it is critical to get all those sketched models off people's geographically-challenged whiteboards and into some medium where they can work with their globally spread colleagues. Software development is becoming an activity that is rarely practiced solely within a single office building and I don't see that trend reversing anytime soon.
Incidentally, I also see it as a convenient way for those who are keen on pair programming to move into another key user experience, the "model as development artifact" space, with better tool support than they have currently from IDEs and text editors.