Folks over at superuser told me to ask this here.
(1) Start here: https://superuser.com/
Hit "sign up"
(2) "Do you already have an account on one of these sites?"
Click the logo for "StackExchange"
(3) Fill in email addr & pwd, hit "sign in"
(4) I get:
SuperUser Log In
Not Found This page could not be found.
I refresh the page and end up back on (3)
Mind you, during all this I am already logged in to StackExchange: https://stackexchange.com/users/1774372/diagon
I am using google chrome on Ubuntu 12.04.