[ignifero]

Do an online poll and ask people "Do you know your openID" vs "Do you know your email". Users are trained to use emails for login, and that's a significant investment already.

[TillE]

That was a brief failure of communication when OpenID was new.

Have a Google or Yahoo account? Your email address is your OpenID. Of course nobody is going to manually enter an OpenID URL. Why would they need to?