Why do I have to log in to each site individually?
If I were to clear my cookies, the first time I visit each SE site, I need to login to each site. This can be a little annoying.
First, I go to SO, I have to log in there. Not a big deal.
I want to check what's going in Meta. I go to perform some action and I realize I'm not logged in. I think, well this is kind of annoying, but it is only a few clicks.
Now I go to my network profile and click accounts because I want to review my accounts on other SE sites. SE obviously knows all of these accounts are linked because it shows them to me. So I open each one I want to view in a new tab. I go to each of these tabs, expecting to be able to use the site, but I need to log in again, for each one.
Why? They are linked, the system know this, and I am already logged in.