This does sound really cool. But there are as well many issues with it.

Pros:
For the most part its free.
Anonimity(sp?)- since you really have no identity if used for p2p it would be hard for mpaa or riaa to track you down.
Easy access to the network(in most areas that is).



Cons:
Privacy- the traffic would have to be highly encrypted because we would be sending our data through a system that isnt being run by a professional company but rather by someone we know little or nothing about. Without safty, identity theives would have a field day.
Dependability- Ideally it would act like the internet. But the internet would have many more rebust ways to route traffic. We all know that gnutella many times get weak links that cause problems. Imagine if 100 people are got the feed off of one guy and he shuts down for some reason. In smaller areas or even some suburbs this may well be the case.




If this really gets worked out, this could really help out alot of people. Not just file traders, this could bring the net to many more people.