Also in the same thread: it had been previously used in Win XP for SSDP, and (directly below) it has been used around the same time in early OSX for mDNSRespond

Also in the same thread: it had been previously used in Win XP for SSDP, and (directly below) it has been used around the same time in early OSX for mDNSResponder (Bonjour/Rendezvous related). So, yes, stick to 8080 and friends. There is a reason for this.