Thank you all for the feedback. The first thing to mention is this follow-up post that feedback inspired. Give it a read!:

Broadcasting From the Mac Without Nicecast

Eric: We believe that providing a retired application which is entirely unsupported, and will likely have more and more issues over time, would be a grave disservice to users. We're encouraging folks to find more viable long-term solutions instead. To that end, we've written about what's available now.

Jim: We're certainly sad as well. We'll see what comes along in the future, but have a look at the follow-up post mentioned at the top of this comment as well.

Kieran K: Thanks for the kind words and memories! It's been a great little tool, but sadly, the world has largely moved on. Now, we must do so as well.

Charlie WIlson: You can definitely keep using Nicecast for quite some time, particularly if you keep the Mac its on in stasis. Have a look at the follow-up post mentioned at the top of this comment as well.

dB: As Quentin noted, “porting” Nicecast to 64-bit would essentially require a full re-write. It is unfortunately not viable.

Rob: I'm afraid so, but do see the follow-up post at the top of this comment.

Chris P: I definitely share that sadness. However, if you don't update the Mac in question, Nicecast should continue to work for years to come.

As far as more modern solutions go, please do see the follow-up post at the top of this comment. We discuss currently available options including using Audio Hijack (which would give you the recording component you're looking for).

Kelly: Loopback, as well as a combination of Loopback and Audio Hijack can definitely help replace Nicecast. We've written about it in the follow-up post at the top of this comment.

Ferris: We're sorry to see Nicecast go, and we know it will impact folks like you in an unfortunate way. As mentioned, do see the follow-up post at the top of this comment. It will help you keep broadcasting from the Mac.