>I was trying to log on to the thread at work and it wouldn't allow my password for a different email address than I used at home, so I thought I had to create a new account for each different email address. So how do I log on if I'm at a friends house, and the login screen tells me that my password is invalid for that email address?

I am not following you here. The login has no relation with your email. Just enter the username and password to do your Universal Thread login.