There’s a new Gmail feature that Google just rolled out that apparently has taken years of testing. It’s the ability to track and sign out other Gmail sessions that you have open in other browsers/computers.
All you need to do is head down to the bottom of your Gmail screen and click the Details link near your “last account activity”. It will show you other Gmail sessions, including their IP addresses and a button to sign out of those sessions.
I tried this today and signed myself out of my session that I left running on my home computer. I love it. It means I can be a little less afraid of using Gmail on strange computers. Not completely though!