Take the music industry. It thought it could stop illegal downloads by showing people how big the problem is. So the industry association’s website sternly warns people that “only 36 percent of music acquired by U.S. consumers . . . was paid for” and that in the past few years “approximately 30 billion songs were illegally downloaded.”

But I’m not sure that message had the desired effect. If anything, it may have the opposite effect. Less than half of people are paying for their music? Wow. Seems like you’d have to be an idiot to pay for it then, right?

Rather than making the private public, preventing a behavior requires the opposite: making the public private. Making others’ behavior less observable.

-Contagious, p.152