> True, the fact that URLs identify them confuses some people. However, http:// being usually superfluous, I don't see why roger.example.com is more confusing than roger@example.com.
Because "roger.example.com" is a webpage, whereas "roger@example.com" is an addressbook entry. Very occasionally, "roger.example.com" is a blog or personal webpage and thus probably refers to a single person. Maybe.
additionally, it may be example.com/roger or example.com/openid/roger, the regularity of it is small, and people already know what their email addresses are.
Because "roger.example.com" is a webpage, whereas "roger@example.com" is an addressbook entry. Very occasionally, "roger.example.com" is a blog or personal webpage and thus probably refers to a single person. Maybe.