Yeah, that sounds like the best choice. (That's the SLIP framing approach.) SCTP probably isn't viable if you want random people to be able to watch the presentation without rebuilding their kernels, and multicast IP isn't viable on the global internet. An IRC server would work fine, and you might even be able to just use a secret channel on Freenode, but some places block IRC because of other pubsub software that uses it.
Right, the benefit of using IRC is that you don't have to write the server; there are dozens of well-known, actively-maintained free-software servers, they're well-documented, and they already support epoll and kqueue and have reasonable ways of handling all kinds of pathological network conditions. But maybe a simple asyncio-based event loop, or even threads, would be fine for itsalive.
