I had a few issues today when signing up
1) my selected username and password did not resultin mailing of an authorization email.
Trying to sign up again does not work because it says the uid is taken of course.
There should be a re-send authorization link to simplify this perhaps.
2) Registering a new website was simple, but on the final JSP page loging in and transferring you to the domain you log in to does not do an acutal referral just sits there and looks in general blank.
I use Firefox 2.0.0.11 on Windows XP to log in