A rather unique idea I ran across the other day is a site which allows you to send a one time 'self destructing' message. Using Privnote, you simply create a message you want to send and it generates a link for you. You then email this link to whomever you would like to read the message. After they have read the message (by clicking the link), the message is automatically 'destroyed' so the link will not work anymore.I really cannot think of a practical application for this, but it is a pretty interesting idea.