Nondisclosure agreements (NDAs) have long been used to protect the trade secrets and other proprietary information of businesses. Increasingly, however, they are also used to protect personal as well as business information — and even matters of national security.

The raciest use of an NDA in recent years — or perhaps ever — was in the hit movie Fifty Shades of Grey, in which the hero requires the heroine to sign one before revealing his big secret.

According to a professional dominatrix interviewed by Rolling Stone in connection with the movie, NDAs of this type are available for download on the Internet.

“Fifty Shades” of Leadership

According to Fortune, this yields one of “7 Leadership Lessons from ‘Fifty Shades of Grey’”:

The best CEOs recognize risk and figure out ways to manage it…. Still, there is being risk tolerant and there is taking unnecessary risks that can jeopardize a business.

As reported by the New York Times, “domestic” NDA’s are becoming a thing, especially in Silicon Valley. For example, workers at the site of what is believed to be Mark Zuckerberg’s new home in San Francisco were apparently required to sign one.

StingRay

Another unusual use of NDAs involves a surveillance tool being used by law enforcement.

As discussed in the Times, in order to buy a gadget called StingRay or KingFish, police departments must sign a nondisclosure agreement preventing them from talking about it.

The StingRay device is small enough to fit into a suitcase. It acts like a cell phone tower and intercepts cell phone signals. It can capture texts and emails as well as calls.

The NDA is intended to prevent criminals and terrorists from learning enough about the technology to circumvent it. The FBI reportedly oversees the NDA with local law enforcement agencies.