An experimental Gmail feature applies the “five-second rule” to potentially embarrassing e-mails. “Undo Send” allows e-mailers to recall an accidentally sent e-mail within five seconds of originally clicking “send.”
This feature, which can be applied when using the Gmail Labs program (an optional program with a array of special feature tools available through Gmail’s “settings” tab), is intended for those who accidentally click “reply all” instead of simply “reply,” or immediately notice errors or spelling mistakes.
Source:
