> 99.9% of websites on the Internet will only let you create one account for each email address. So if you want to see if an email address has an account, try signing up for a new account with the same email address.

That's terrible UX.

> But there's a tradeoff there between security and UX, I hear you say. I am trying to show you there is no tradeoff; you are choosing between a better user experience and a worse user experience.

I didn't reach this conclusion at all. Am I missing something?