Gmail Lets You “Undo” Sent Messages

Gmail "Undo Send" is yet another awesome new feature in Gmail Labs
After enabling the feature, Undo Send works much like Gmail’s other “undo” features. When you send an email, you get a message confirming it has been sent, along with a link to “Undo.” This message lasts for 5 seconds, at which point you lose the opportunity to take it back.

While that might not be much time, it’s probably enough to pull back emails where you forget an attachment, forget to cc someone, or catch an obvious typo.

This feature, though, isn't going to help with those Regreat-Mails (email you soon regret that you sent at all). For that, check out Googles labs for Google's Mail Googles

Mail Goggles requires you to solve some simple math problems before you can send mail. Obviously, this gives you some time to let it sink into the gray matter that you probably don't want to send that email anyway. After enabling this feature, you can adjust the schedule in the "General" settings page.

Find and read more about what cool gadgets Gmail has to offer in the Official Gmail Blog