Auth system that allows a user to add a password later?

Question

Two goals:

• Minimize barriers to writing comments. Obvious design conclusion: don't make your users create a new account or login with a password.

• Allow users to accumulate karma/points for comments. Obvious design conclusion: have users create unique accounts so you can reward their activity.

How have other people resolved this? Do you think it's a good idea to design a system that saves email addresses, then allows folks to associate a password with them later on?

Answer 1

Check out how disqus do it. They don't force you to register, but they make it very convenient to.

Answer 2

Are you asking for an email address? If you are the process can be:

function emailverify() {
    // Send a verification email or use http://email-verify.appspot.com/
    // Hold their comment until their email is verified.  Once verified, post comment
}

if(we have seen this user before) { //ie, email is in DB
    if(user has password) {
        // Ask for password
    } else {
        emailverify();
    }
} else {
    emailverify();
}