Tell a friend, tell a foe, tell a ho.
Tell any fellow, and do the right thing like Danny Aiello.
Basically what WarFighters says is the way to go. Post it on your facebook wall, tag people if you have to, just make sure that as many people get to see it. Remember, if you tag a person on FB, your friend's friends can see it too. So you may well be reaching ballers that you don't personally know.
And if you are feeling particularly adventurous, post it on TB/SL's page(s) as well. It will be gone soon, but anybody that sees it, could be a person rescued.