Apple Thoughts: Take Back That Mistaken Gmail!

"Did you know you can undo a sent e-mail in Gmail? It's a lesser known feature, but Google just made it even better than it was before. When it first launched, you were given a 5-second window during which you could hit 'undo.'"

It's a handy feature, and now you have about 30 seconds in order to take back that mistaken email, that is if you have gone into the labs area and enabled the setting, as they are showing above.