Gmail helps users avoid e-mails they'll regret

There are many obvious things people shouldn't do after drinking alcohol. Sometimes, sending e-mails should be on that list.

Of course, we're not talking about yours truly -- but rather, people like Jon Perlow, the Gmail engineer who came up with "Mail Goggles," a new feature for users of Google Inc.'s e-mail client who want some extra safeguards in place to avoid sending messages they'll regret. (Examples of such e-mails include, in Mr. Perlow's case, the time he "told that girl I had a crush on her over text message" or when he "sent that late-night e-mail to my ex-girlfriend that we should get back together," according to his confession on the company's Gmail blog.)

Here's how it works: Once enabled, Mail Googles asks users to solve several math problems after clicking send to verify that they are "in the right state of mind." Users can customize the time settings, but by default the feature is set for late nights on the weekend.

To activate it, sign on to Gmail, go to Settings, then click on Labs and scroll down to Mail Goggles.