Sunday thought experiment: Your email address is a public endpoint that anyone in the world can write to for free. Your phone number at least has a cost to acquire. What if your inbox worked like your front door? Strangers knock, you decide if they're worth your time. But right now, email is more like a mailbox with no lock — 160 billion spam emails hit inboxes daily. TANSTAAFL fixes this with one simple rule: strangers pay 100 sats (Lightning) to reach you. Friends and trusted contacts pass through free. The payment isn't a fee — it's proof of intent. Every gated inbox makes spam more expensive. Every payment goes to the recipient. The incentives are perfectly aligned. Try it: tanstaafl.email #bitcoin #lightning #email #privacy #spam