Not sure if you understand how Unite works from a bandwidth/usage standpoint. Check out Brett's post above:
It is *not* just like p2p. It is a proxy cache. Opera's proxy cache, keeps a copy of the object until it is replaced or updated on your machine. Your machine only fesses up one copy of it to the proxy cache. Everyone else pulls from the cached copy. Thus, it is not a true "web server". You could serve a picture a million times off your feed, and all you do is send one copy to the proxy cache server. This is *really* what Opera Turbo was testing in the beta tests (the proxy caching mechs).