I once worked for a P2P company, and we employed our own "supernodes" in the field too. They played a variety of roles, amnog them, act as a distribution point for latest upgrades to the desktop P2P software. So, yes, this is not unique to Skype.

Aswath,

There is a company called "damaka" (http://www.damaka.com) that have figured out a better way to crack the P2P puzzle. They have completely eliminated the concept of supernodes and thus removed any dependency/cost involved in maintaining such relays.

Using supernodes (at eBay or anywhere else) to relay data is potentially dangerous and can be considered unethical by some. This explains why Skype was not able to penetrate the enterprise market.

According the Podcast by damaka's senior advisor Alastair explains how they are different from (better than) Skype. damaka uses the concept of "direct peering". (Check ou tthe podcast at http://www.damaka.com/news.htm)

I have used damaka with my friends in the US and in UK, Canada and Australia. Its audio quality is much better than Skype. And they claim to be completely standards-based. Give it a shot!

~sippedoutyoda~
...may the force be with you...

sippedoutyoda:

I have known damaka, but haven't quite figured out how they are doing what they claim they are doing. For example, in the podcast, we are told that initially the ysers register with a central server and at that time the client is informed of the buddies' status. So I presume that subsequently the clients query each other. But then, when the host commented that you offer presence service, the guest agreed. So I am not sure.

They say and you seem to suggest that there is no need for relay nodes ever. The details are hidden due to the pending patent. Unfortunately, the application is not yet available at the patent office for public viewing. But without the details, it is not clear how one can assure "ALL" NAT/FW can be traversed. Remember, Skype maintained this as well; but later on others narrated the restrictions. I firmly beleive that either you need relay nodes (at least temporarily) or you have to do something special somewhere. So I remain skeptical.