This from the BBC.com site: SMS text messages that 'self destruct' about a minute after they are received/read:
Londoners have subscribed to a self-destruct text message service which started on Sunday in the UK. The commercial service allows sensitive messages to be destroyed 40 seconds after being read. It's called StealthText.
"The technology behind StealthText is derived from military technology, so the comparisons with Mission Impossible are justified," said Carole Barnum, chief executive of Staellium UK.
"The ability to send a self-destruct message has massive benefits for people from all walks of life, from everyday mobile users through to celebrities and business people," she said.
People interested in using the service to send messages have to register and download a small program onto their mobile phone.
Once a message has been sent, the recipient receives a text notification showing the sender's name and a link to the message.
After they have opened it, the message disappears after 40 seconds.
Despite the fact the message will be removed from phones, users cannot entirely avoid a data trail. For legal reasons, a log of the message will remain on a secure server to which they have no access.
Aha. So it's not really gone. But, thanks for letting a guy like me know what to ask for in discovery now.