Before you panic too much, Evil is a great implementation showing the lack of privacy controls most people place when posting information, such as phone numbers, into their stream. Evil simply scans Faceook, blocks half the number for security and shows them at random on a webpage with an avatar of the person as well.
The site owner also does a great job explaining how it works, how anyone could do it, no tricks involved and what parts of the Facebook API he uses to make it all happen. While phone numbers can easily be changed by anyone in today;s world for security, it is amazing how much information is now tied to it and shows when doing searches in Google sometimes.
So go into the new privacy settings and beware what sharing selection is made when you make a post on Facebook. If you have doubts, simply send it via a private message instead.