Multicast won't become pervasive until there are applications that use it (as has been pointed out in this thread), and those applications won't be widely-used until there is some momentum with high-speed connectivity (ie > 1Mbps and probably more like 10+Mb/s). Many multicast applications (primarily research/education networks) are for interactive communication, and useful interactivity requires lots more bandwidth and much lower latency and jitter than is available even on cable/DSL. If you have a chance to see what's going on with multicast (and anything else) on Internet2, you'll see what happens when bandwidth and latency become less-significant problems. The expansion of Internet2 to diverse disciplines as well as K-12 and non-research higher-ed schools will expose a larger and more diverse group to these applications. Though IPv6 uses multicast more than IPv4, the default use is basically a replacement for existing broadcast-based functions (ARP, DHCP, etc). IPv6 will not magically solve multicast problems outside the local subnet. Multicast being integrated into IPv6 will probably make it more palatable than it is now. Pete.