There is a service, which I never knew about, but is working well enough is “Extortr – Online Blackmail for the masses”. The services eases the job of “how to blackmail efficiently”. The idea is that you take a photo or video of someone worth being blackmailed about. Then upload that scandalous video to Extortr and email your demand to the victim. He can check this video online himself/herself. If they pay-up the video will be deleted, else it will be made public for everyone to see.
Blackmailing made simple online @ Extortr
(btw at the bottom of the site it is written “This isn’t actually a genuine web site. It’s just a joke.” Heck! I think it is a brilliant idea, and should pop-up a new generation of YouTube nation -> YouBlackmail.com ? )