One night after much drinking, Google engineer Jon Perlow sent an e-mail to his ex-girlfriend asking her if she’d take him back. Apparently it didn’t turn out very well. So Jon decided to spare others such embarrassment and grief, so he came up with Google Mail Goggles.

In Perlow’s own words: “Hopefully Mail Goggles will prevent many of you out there from sending messages you wish you hadn't. Like that late night memo -- I mean mission statement -- to the entire firm.”

The concept behind the Google Labs application is simple: when enabled from Gmail’s settings, it will ask you for what times it should double-check that you want to be sending e-mails for which you’ll hate yourself in the morning. The default is Friday and Saturday evenings until 3 a.m., but it can be configured for other hours and days of the week. When it’s active, trying to click send on an e-mail will prompt you to take a simple math test – some basic addition, subtraction, division and multiplication; no trigonometry or calculus involved – and if you fail to solve it in under 60 seconds, you’ll be unable to send the e-mail.

The concept is that you won’t likely be able to solve the test quickly enough when drunk, so the Goggles should help you avoid sending an enraged resignation letter to the boss, or a groveling e-mail to your girlfriend begging her to make up with you, or anything else you wish you hadn’t sent. Pity Mail Goggles doesn’t require you to take the math test when disabling the feature in settings.

KPIX TV headed out into a local pub, laptop in hand, to see if users could solve the test, and to get opinions. The results were telling: none of the people who had been drinking managed to do the test in time. As for the opinions, they were mixed – some hailed the idea as a potential lifesaver, others hated it. The feature is nevertheless strictly optional.

This isn’t the first time a company has come up with a way to deal with inebriated messaging. Virgin Mobile comes to mind, as they’ve been offering Australian users the option of blocking calls to certain numbers during late-night numbers, and LG even marketed a phone in Korea which had a built-in breathalyzer.

The Google Enterprise version of Gmail also has this feature built in, and it may well make a late-working employee, who although is not drunk, nevertheless think twice about sending that enraged internal email giving his incompetent co-workers a telling off.

Mail Goggles may not be a fool-proof system for saving face, but it will make you think a bit before emailing emotionally, and that’s as good as a friend who’s always there to tap your shoulder.