Most of peoples log on their gmail account on many devices like desktop, laptop, mobiles or others systems.
If you used gmail on someone's phones or system and you forgot to logout and you want to logout from gmail account at those devices for this here is a trick.
1. Open your gmail from desktop or laptop.
2. Scroll down to the bottom of your inbox you will tiny print "Last account activity." Click the link "Details" right below it.
3. A popup window will be open and press the "sign out all other web sessions" button to logout from your gmail account open on other devices. You can also view a list of devices that have signed into your Gmail account recently underneath this button.
