Here is a solution to those who divulge there password to someone else and find whether they are checking your gmail mailbox. This feature enable us to even sign out remotely if someone is logged into your gmail right now. If you are signing in your account from different system don’t worry the activity is logged and you can sign out remotely if forget to do so.
At the bottom of your inbox you can see the status of your last activity of your account. It will display an information of the IP address if the account is logged in some other system.
In the figure above it is showing an IP address that means your account is logged in another location. For instance let it be in my office. Click on the details link.
On the top of you can see a concurrent session information which shows the current activity of your account. You can see the Signout all other session button if some other session rather than the current session is opened. By clicking the button your remote session will be closed. Table below shows the recent activity.