Need to determine what's a valid name at compile time
We know that quoted processes are valid names
URLs are valid names, but I shouldn't be able listen on https://www.google.comand expect to intercept messages meant for google
We need to have some kind of a registry to determine what formats of names are valid (e.g. do we want names that *aren't* URLs or quoted processes? Can we encode site-specific constraints about URLs?) and a way to denote policies around sending & receiving on those names.