Possible Duplicate:
Why reputation is not passed between superuser, stackoverflow and serverfault?
Why am I not permitted to downvote, comment, or use community wikis here on SU (yet) when over on Stack Overflow, I am?
For a network that loves single sign-on solutions like OpenID, doesn’t this seem rather inconsistent?
It’s not like SU can’t trust that my reputation on SO is genuine, you know? And it’s not like they are wholly separate entities — the little StackExchange widget at the top left shows me notifications from across the network!