Bittorrent is the opposite of multicast. Instead of aggregating the data into a single channel to save bandwidth, we instead split it up across every single recipient in a huge NxN graph.
This also illustrates the other problem with multicast on the Internet: It's mostly saving bandwidth on the backbone and at the server. The backbone has plenty of bandwidth to spare, and servers are often in data centers these days where bandwidth is not a huge concern.
The use case where someone does video production in their basement and broadcasts it out to millions of people across the internet over their home cable modem connection is just not compelling enough for ISPs and the backbone providers to make Multicast happen. Just put it on Youtube and let Google sort it out.
This also illustrates the other problem with multicast on the Internet: It's mostly saving bandwidth on the backbone and at the server. The backbone has plenty of bandwidth to spare, and servers are often in data centers these days where bandwidth is not a huge concern.
The use case where someone does video production in their basement and broadcasts it out to millions of people across the internet over their home cable modem connection is just not compelling enough for ISPs and the backbone providers to make Multicast happen. Just put it on Youtube and let Google sort it out.