Undo Send Messages In Gmail
The folks behind Gmail Labs have added a new update to Gmail, using which users can revoke sent messages and stop delivery of the messages.
This feature can be used by quickly clicking on the Undo link next to the Your message has been sent, however the message can only hold the email for about 5 seconds, before the message is sent on its way.
A similar Gmail Labs feature called Mail Googles stops tests your ability to send messages on the weekends, when you have just come back from a drinking spree :-).
To activate the Undo Send feature, go to Settings > Labs and enable the Undo Send labs feature.
New In Labs: Undo Send [Gmail Blog]
Author: Keith Dsouza 
