Note that video caching systems like P2P networks can potentially serve video to extremely large numbers of users while consuming reasonably low levels of upstream bandwidth.
The total bandwidth used is the same though, no escaping that, someone pays.
This is not true. Increased bandwidth consumption does not necessarily cost money on most ISP infrastructure. At my home I have a fairly typical ISP service using BT's DSL. If I use a P2P network to download files from other BT DSL users, then it doesn't cost me a penny more than the basic DSL service. It also doesn't cost BT any more and it doesn't cost those users any more. The only time that costs increase is when I download data from outside of BT's network because the increased traffic reaquires larger circuits or more circuits, etc. The real problem with P2P networks is that they don't generally make download decisions based on network architecture. This is not inherent in the concept of P2P which means that it can be changed. It is perfectly possible to use existing P2P protocols in a way that is kind to an ISP's costs.
If it was only redistributed locally. Even in that case it's not helping much as it still consumes the most expensive bandwidth (for UK ADSL). Transit is way cheaper than BT ADSL wholesale, you're saving something that's cheap.
I have to admit that I have no idea how BT charges ISPs for wholesale ADSL. If there is indeed some kind of metered charging then Internet video will be a big problem for the business model.
Or the caches that are being sold to fudge the protocols to keep it local but if you're buying them we could have just as easily done http download and let it be cached by existing appliances.
The difference with P2P is that caching is built-in to the model, therefore 100% of users participate in caching. With HTTP, caches are far from universal, especially to non-business users. --Michael Dillon