Why separate Stack Exchange accounts?
This is intended as feedback, not a question.
I tried to vote up a question on Superuser.com. I need to login. Okay fine, I use StackOverflow all the time. Wait, why am I not already logged into StackExchange? I am already logged in on StackOverflow!
Okay, fine I am willing to log in again. I use the email I use on StackExchange. This does not work. Not only can I not login on StackExchange, it doesn't even recognize my email. I spent a bunch of time going back and forth and verifying my email is the one known by StackOverflow, and typed it in a dozen times to make sure yes, I typed it in correctly. I also try to type my StackOverflow user handle, which is not even recognized as valid format.
As far as I can tell from the documentation and branding shown to me, StackExchange should recognize the email I use with StackOverflow; even better, the user handle also.
(What I eventually found to work was to use Google OpenID to verify my identity. I was worried that this would create a second, useless account. Luckily StackExchange did recognize that the two accounts should be merged.)