Your email address is not a username. It’s a fingerprint.

Unlike a password, you can’t rotate it. Unlike a username, it follows you across systems, survives account deletions, and persists in breach databases long after you’ve forgotten you ever signed up. Hand it to enough services and it becomes the thread that ties your entire digital life together, quietly, invisibly, until someone pulls it.

Most people treat email like a mailing address: something you give out freely because that’s just how it works. It isn’t. It’s a persistent, irrevocable identifier that you’re voluntarily handing to strangers, and the only question is how many of them will eventually misuse it.