Nicholas Thompson and Fred Vogelstein writing for WIRED
Near the end of their exchange, Zittrain asked Zuckerberg what Facebook might look like 10 or so years from now. The CEO mused about developing a device that would allow humans to type by thinking. It sounded incredibly cool at first. But by the time he was done, it sounded like he was describing a tool that would allow Facebook to read people's minds. Zittrain cut in dryly: "The Fifth Amendment implications are staggering." Zuckerberg suddenly appeared to understand that perhaps mind-reading technology is the last thing the CEO of Facebook should be talking about right now. "Presumably this would be something someone would choose to use," he said, before adding, "I don't know how we got onto this."
This is the end of the article, which sums it up pretty well.