Well this is one feature that I believe is going to be a killer feature as far as web-based e-mail security is concerned. Gmail will now list all the recent sessions with IP addresses.
It will allow users to check if their account has been accessed from some strange computers.
Also, Google will list details about sessions (if any) that are concurrent to your sessions and will even allow you to log out of them. Specifically useful as it will allow you to be aware of the fact that in your sleep you have blurted out your password to your girlfriend and now she keeps a tab on your mails and Gchat transcripts
For more please see:
Last account activity - Help Centre
How you can access this feature:
1- go to Details tab in footer and click it
Pics:




It will allow users to check if their account has been accessed from some strange computers.
Also, Google will list details about sessions (if any) that are concurrent to your sessions and will even allow you to log out of them. Specifically useful as it will allow you to be aware of the fact that in your sleep you have blurted out your password to your girlfriend and now she keeps a tab on your mails and Gchat transcripts

For more please see:
Last account activity - Help Centre
How you can access this feature:
1- go to Details tab in footer and click it
Pics:



