Sorry for getting in late on this but... The argument that multicast should be billed based on the number of receivers is flawed. Those receivers are already being billed based on the bandwidth they use regardless of source. In other words, the multicast source is not, as someone suggested, using more backbone that it is paying for. Everyone receiving a multicast feed is also picking up the cost of their respective traffic. Bottom line is, for certain problems, multicast is simply much more efficient than unicast. There are already killer apps, but there also seem to be killer obstacles. Network providers are fully aware of the burdens of unicast. But since they make more profit when their efficiency is up and their customer's is not, they'll lean to keep that balance or try and charge more for offsetting it. It will probably be a while before it is promoted as the better solution. -John