How to undo sent email?

Instead of hitting "reply" to an e-mail, we accidentally push "reply all," sending a potentially embarrassing or insulting message to those we didn't intend to see it.

To address this problem, Google Inc.'s Gmail Labs has launched an experimental feature called "Undo Send" that gives users a chance to rewrite their message, correct settings or simply fix typos.

When a Gmail user who enables this feature sends an e-mail, a button that says "Undo" will pop up on their screen for five seconds. If the user hits the button within that time, the service will retrieve the e-mail in draft form -- allowing the user to make changes or cancel the message altogether.

Read the rest here