Secure Collaboration: What's it mean to you?

I'm wrapping up my current project in the next couple of weeks and starting to think about my next project.  This next project will focus on "Secure Collaboration".  I've got some ideas about what we could do in this area, but the most important thing is to help solve our customers' problem.  Therefore, I'd like to know: when you think about secure collaboration, what do you think about?

I'd really appreciate any feedback on this topic.  What guidance and tools would really help your organization collaborate securely, especially with people outside the firewall (customers, suppliers, partners, employees, etc.)?

By the way, I am going to be hosting a side meeting at Tech Ed to get input from customers on this topic.  Let me know if you are interested and you're going to be at Tech Ed and I'll make sure you get an invite.

Thanks!