SCTP does two things that I think are hugely important.<p>First, it provides a datagram/record transport that is TCP-friendly. The most important thing TCP does isn't reliability; it's the insanely complicated interpretive dance it performs with other TCPs to keep them from melting the network. Right now, your only scalable transport option is TCP, which means you're boned if you want real-time.<p>Second, it provides reliable out-of-order delivery, which is exactly the happy medium that I assert without evidence 99% of UDP apps actually need. Reliability good. Enforced ordered delivery bad; means updates lag behind stale data.<p>The big issue with SCTP is that firewalls will block it.