Try Scrambls on Facebook, or www.scrambls.com You can only read something that has been scrambled if 1. you've exchanged email addresses and 2, the person doing the scrambling wants you to see the message in the clear.
SKS does both. I imagine he sends some to members of the staff which are scrambled and I can't read, and he occasionally sends some which I can read that indicates where he is or that he is testing some aspect of the system.