content: I'm going to post a more detailed response to this on /v/Technology, but I can outline a few points. The license plate applies to public roads. It does not apply to private tracks. Ever see a license plate on an Indy car?  Now, what is the communication? Does it travel on public networks? It can. It also might not, depending on details like where you put your mail server and where you're mailing. So the proposal is for some authentication and non-repudiation among email addys. Okay. The proposer isn't going to be happy about encryption, either. The difference, though, is that one cannot tell by looking at your car where you've been. Two emails back and forth "proves" a connection, but that enables a lot of specious conclusions.  Here... imagine that Osama bin Laden has identified me as a superpatriot. He writes me an encrypted note: HAHA, I bomb your tower great american devil. I reply with an encrypted message: You are bad mudslime sand nigger! I will become president and bomb you. Now, for obvious reasons, I don't want to admit I wrote that shitty message, but without revealing the contents, I can't really clear my name. So, when I'm running for president on the Make America GRRRR-eat Again! platform, a journalist from the Real American News can ask, "We know you're email besties with KNOWN TERRISTS! What say you?" I'm stuck. After "You're a great American..." do I alienate black voters or egg on the conspiracy crowd? That's the difference. Your car doesn't tell everyone it was parked in the Nickanee, Alabama Motorlodge's parking lot while they hosted a Klan rally.