Say I compromised a website that was storing passwords in the clear. There should be no way whatsoever for you to know I've done this, or even that I've -used- this password. What, if any advantage would you have over a password manager storing single-use passwords? A very good web implementation of this, with client-side encryption so that the service has no access to your actual passwords, is clipperz.com. Do you believe you can offer me something better? As someone who spends a lot of time studying security, I think you've made some extraordinary claims..