Seriously...I've been giving some thought to this since I saw this article. It's probably a lot to ask that Internet providers have a reasonable multicast implementation, especially for more than a single segment (such as a single CMTS).
I wonder if it would be feasible to distribute session encryption keys much the same way they're determined/exchanged for IPSec (IKE). This sort of thing alone (IP broadcasting) could be the single biggest, best reason to transition to IPv6 as quickly as possible. The more vast address space would be necessary to implement something like the ability to send specific multicasts...not just well-known ones like NTP, RAs, and such. Imagine if you will that ABC, NBC, CBS, Fox, USA Network, Lifetime, HBO, SyFy, Discovery, etc. all had their own multicast address, and that all one has to do is send messages to join the multicast group, possibly also doing some sort of encryption key exchange if necessary for entitlement purposes. -- English is a difficult enough language to interpret correctly when its rules are followed, let alone when a writer chooses not to follow those rules.