Shoutcast is still around, but it’s proprietary and costs money. It’s still a viable alternative to Icecast but I think you’ll find more Icecast based services around simply because of the price. That, and Icecast has been around for a long time, so it’s kind of a known system. But yeah, tens of thousands of audio and video feeds still run on Shoutcast. They even have a directory to help you find them.