I came across this today http://offsystem.sourceforge.net/
It's a P2P system where data blocks are traded not files.A file becomes a set of blocks and if requested, anyone who has the block can supply the data, even if they don't possess the same file.
In that way no-one is sharing copyrighted material in the large, just coincedent blocks.
I've not pushed any mpeg data into venti, though I have idly wondered if there are any disk saving.
