Earlier quoted context omitted.
Yup. But they do mention it when installing. You can also disable it. If you are not firewalled or NATd you are a supernode automatically - on the plus side you get better sound quality for voice calls. Normally the bandwidth used is pretty low since you are mostly forwarding text messages. When they said mega-supernodes they meant machines controlled by them that do nothing else, and are on high bandwidth connection…
I've looked around for the ability to turn off supernode on Linux and Mac clients for a while but have come up empty. Do you know which section of the preferences/settings it's supposed to be in?
https://www.cs.uwaterloo.ca/twiki/view/CF/SkypeConfiguration...