Gmail's Undo Feature

Have a habit of doing things like accidentally including the boss in that last group email about what a doufis the boss is? Gmail has a solution for you.

Kind of a low tech solution. But since this is Google, maybe they'll serve up a relevant ad from a writing service right after you press undo? Or perhaps, if the email was really late at night on a weekend, an ad from a company that sells a tonic to cure hangovers?