BitTorrent and RSS Enclosures
BitTorrent would be an awesome way of distributing RSS enclosures. Someone posts a large file, and all the clients that are configured to retrieve it start working together to retrieve it in an incredibly efficient manner.
One of the problems with RSS is that it won't scale - if my weblog suddenly becomes popular enough that ten thousand people subscribe to it, that would pretty much kill my internet connection (10k people's aggregators polling every 15 minutes).
Imagine I had those 10k users and I included a 1 meg RSS enclosure. There goes my 10 gig file transfer limit for the month.
But with BitTorrent, I'd use a fraction of that, because those 10 thousand aggregators would work together (using the BitTorrent protocol) to share the load.