"...On my Mac, my choices of threaded Lisp implementations was limited to OpenMCL, and in FreeBSD it's CMUCL. Because of the low-level socket and threading code we had to write, reddit would not run on my Mac, and I was always tethered to our FreeBSD development server. Not being able to program offline is a pain."

Interesting choice; the reddit guy gives up Lisp for python rather than Mac desktop for a BSD/Linux desktop. I would rather do the reverse; would move where Lisp works great on client and server.