Please post your full name, date of birth, full address, and telephone number (plus cell phone number, if you have one) to your journal, as the first chronological entry (backdated) in your journal, with Private security, and leave a note in your userinfo indicating that you've done so. The life you save may be your own. In the event of an emergency, LiveJournal administrators can view this information -- and please believe that it is only used in the event of an absolute emergency. But you'd be surprised how many of those there are on a service with four million users. And in an emergency situation, every second counts.
Yes, the Abuse team occasionally hears of users who plan to commit suicide, but there are other situations where having this information could possibly be of use to the police. There have been, for instance, phone posts that were interrupted by physical violence before, and other such situations. The Abuse team often gets reports of these things, and oftentimes, there is nothing we can do to help, because we can't find you.
Please take a moment of your time and make this post. Your privacy will never be violated except in absolute need, and though we hope it will never be necessary, it could prove to be very necessary indeed.
Also, remember to make it backdated, dated before your very first entry, and make it private. The private security means that no one but you can view it, and the backdate means that you can date it for whenever you want, basically.
My contact details are friends-only (since I don't feel the need to make them completely private; YMMV) and can be found in a post dated the day I was born.
P.S. If you agree with the meme and want to help it spread, posting it public may be better if you have a friends-only-by-default journal.