Multicast Traffic on Backbones

Don't know why I came across this, but I found a document on Sprintlink's site that says their entire backbone is multicast enabled, and they also peer with the MBONE for multicast traffic. They charge no fee for dedicated customers to be multicast-enabled. Are any other major networks doing this? Or have I been living under a rock and _everyone_ is doing this now? Thanks, Deepak Jain AiNET