While yes, the concept of having a browser add-on is good and certainly a necessity, users should also be able to create an account directly on your site where they can access all of your passwords. Let's say, I go on a business trip and forget my laptop. I am required to use the business center computers at the hotel I am staying at, and I therefore can't download a browser plugin to this machine. I should be able to login to passwordfox.com, see all of the passwords I have stored with the system, and from there, carry on with my business. I think that both a browser add-on and an account on the website are a necessity. You need to differentiate yourself from all of the password generators out there. Feel free to PM me if you'd like more advice, and I'll give you my e-mail. I don't check DP too often