Call it morbid, but I suppose there are a lot of people who want to leave something behind when they pass away. We never know when our lives will end, but there are ways and means by which we can make sure that what we want to say never gets left unsaid.
Enter ifidie, the Facebook app that offers people the chance to prepare messages that will get published on the social networking site even if they are already dead. Famous last words. Life after death (in a way).