One thing I really hate on SE is that, when I want to ask a question about something, and it gets, lets say, moved to another site, I have to click log-in again and enter my open-id again. Can't you guys just make it so that, whenever I login to lets say, SO, I am automatically logged in to the other SE sites (with the associated accounts) by using a cross-domain cookie. This has several advantages:

* Faster
* Less HTTP Requests
* Less human life-time and energy wasted (better for the environment)

It has only one disadvantage (if it is one at all):

* Stimulates lazyness