Fade, described in 'Subversive' code could kill off software piracy, is a new anti-piracy system with two notable features:

Virtual Scratches as Watermark

Fragments of 'subversive' code is laced into the CD in a way that makes them look like real scratches on CDs.  Scratch-aware programs access the CD directly to see if the scratches are there.  Since current crop of CD copying software tries to correct scratches as it copies, missing scratches means pirated copy.

Pirated Copies as Demos

When a pirated copy is detected, the program silently starts degrading it's functionalities.  Degradation speed is set slow enough for the unsuspecting pirate to become dependent on the program and, hopefully, force a purchase.  Degradation probably involves overwriting parts of the program on the hard disk.

While I don't think Fade will make a noticeable dent in piracy, I like the idea of using piracy as a marketing tool.