A good portion of the bandwidth being used on the Internet could be done over multicast if it were widely supported. For example, popular content on Hulu could

A good portion of the bandwidth being used on the Internet could be done over multicast if it were widely supported. For example, popular content on Hulu could be multicast. You'd download the beginning of the video over HTTP but simultaneously tune into the multicast that started the most recently. Once the two streams meet you drop the HTTP connection. If widely deployed this would reduce costs for both Hulu and ISPs, and for places where multicast doesn't work it can fall back to HTTP.