Deathswitch.com, brought to you by Information Immortality, LLC., is a site to manage your final message to your family and friends.  This website is a specific implementation of the advice mentioned in our post on “Sharing your Obituary after your death“.  From the website:

A deathswitch is an automated system that prompts you for your password on a regular schedule to make sure you are still alive.

This used to be a common practice by employees who sneak code into an application to make it fail when they are no longer employed at the company to prevent the “deathswitch” from executing.   In this situation, the use of this system is put to a positive use.  Please keep in mind that this service charges an annual fee to maintain this list.