Google has revolutionised the way that the world searches for information, pornography and Sarah Palin. Now it may have solved a problem that has plagued computer users since the birth of e-mail.
Jon Perlow, one of the search engine's software developers, has come up with an idea that could save 
The problem became apparent to Mr Perlow after he sent a late-night message to his former girlfriend, telling her that he thought it was time that they renewed their relationship. It did not go down well. Working in his spare time, he wrote a programme designed to act like the responsible friend who confiscates your car keys late in the evening.
The program, which he called Mail Goggles, intercepts e-mails sent using Google's e-mail service, Gmail, after a certain time in the evening. “It's that time of day,” the program says. “Are you sure you want to send this?” It then tries to ascertain whether the writer is drunk by asking five mathematical questions that have to be answered in a limited time.