I always log in to Stack Overflow using my Google OpenID.
I went to an Internet cafe and just used Stack Overflow, and when I was finished, I logged out. When I came back to my seat, I found another guy using my Gmail account.
My question is: how can he access my Gmail account even after I logged out of Stack Overflow? I would like to know the technical concept behind this.
I would additionally request that the wording of the log-out message be changed to clearly mention that logging out from Stack Overflow will not log you out from Google. Also, add a hyperlink that explains single sign on.
You can login with any Google, Facebook, Yahoo or StackExchange account that uses any of the emails above.
Clicking Log Out will clear all local credentials in your browser, and log you out on all devices.
I first asked this question on Stack Overflow and I was suggested to post it here.