At present for every piece downloaded, someone has to upload. Most of our connections are asymmetric, typically with download speeds 3-6 times as great as upload speeds.
Would it make sense in the next itteration of the bittorrent protocol to enable short list multicasting -- when you upload, you upload to a list of 4-6 recipients. This effectively magnifies the upload bandwidth.
Does this make sense?
ISPs don't forward multicast like that, so it wouldn't actually work.
The only place it's actually effective is in situations where individuals have multiple internet connections with a backbone between them that is greater than either connection. (Multiple *DSL/Cable connections with a gigabit LAN connection behind the router(s)).
Guy with a few torrent programs under his belt.