In GMail, you can log out other sessions if you're logged in. At the very bottom, it says something like "Last account activity: xx minutes ago ..." followed by

In GMail, you can log out other sessions if you're logged in. At the very bottom, it says something like "Last account activity: xx minutes ago ..." followed by a Details link. Click it and you'll see the button to log out everyone else but your session. Otherwise, I don't think so and am watching this thread to learn.