Just read in the Medium blog:
Every unique home deserves a unique address. So every new profile comes with its own Medium URL. We’ll prompt you the next time you publish a story.
I was impatient to reserve my usual “funcrunch” handle and couldn’t find a setting to do so. Hence this brief not-story.
OK, to assuage my guilt here and answer an infrequently-asked question: Funcrunch is a play on Fenchurch, from the excellent Hitchhiker’s Guide to the Galaxy by the late great Douglas Adams.