Question about Edublogs free, pro and campus differences

I was looking at the Edublogs site and decided I needed a bit of clarification about how the differences are implemented.

I am wondering if "Pro" is the same as "Supporter" and "Campus" is the same as a WPMU "Multi-site?"

Or, is Campus a freestanding WPMU installation?

Or, are they some other iteration?

Thanks,
Kirk