Remember the “beer goggles” feature that Gmail added last fall, to prevent you from sending drunken rants in the middle of the night?
The experimental “goggles” feature requires you to prove your coherence by doing a simple math test before the mail sends.
A related tool was added this afternoon, and this one’s a lot more useful. It also work all the time after you’ve activated it, and not just the middle of the night, like goggles’ default setting.
Gmail calls it “undo send” because it gives you five seconds to halt an outgoing mail, after you’ve pressed send. It only works if you’ve gone to Gmail Labs and activated the feature in settings.
“Undo Send” does for words what the five-second rule does for foods (and pacifiers) that fall to the ground: Longer than five seconds, and out they go. Less than five seconds, you can put them back in your mouth.