Here's a creepy site that is based on a sound idea: JustInCaseIDie. On this service you can set up a message to be sent to a single recipient if you don't check in by a certain time or reply to a reminder e-mail. The idea is that, if you die, you can't check in, and your canned message will be sent. Said message could be a posthumous love note, a terrible expose, the combination to the safe in the house, and so on.
It's implemented in a pretty lightweight fashion, so I can't imagine it … Read more