As we continue to deploy multicast services across the internet, we continue to learn more about the scaling, deployment, and usage propereties of IP multicast. This BoF proposes to discuss two possible architectural enhancements to the existing multicast services which may improve the acceptance and widespread usage of multicast. The first of these is the possiblity of using a two-part global multicast address with the goal of easing address allocation headaches and the use of shared resources in ISP backbones. The second is to provide a slightly different multicast service to groups where there is a single source and thereby achieve greater scalability if there is a large number of such groups. The purpose of the BoF is to air these issues with the community at large and to ascertain if there is sufficient interest in pursuing this direction to form a Working Group to produce corresponding protocol and operational specifications. Some of this work has been presented at prior IETFs and other forums, so the BoF will not be of a tutorial nature (i.e. there will not be presentations of the earlier work on "Simple Multicast" and "Express"). Rather, we will discuss the relationship between these (and other) proposals and the current trajectory for multicast deployment in the Internet as a whole. We hope to ascertain if employing some or all of these techniques could accelerate deployment, or result in higher confidence that widespread multicast will be more scalable, debuggable, and robust. In order to start the discussion prior to Oslo, it would be convenient to use an existing mailing list: sm-interest@cs.ucl.ac.uk. Participants should have read the following material prior to attending the BoF: http://www.cs.ucl.ac.uk/research/rama/