Are 'Dark Networks' a Threat or a Haven Online?

Revelations about the government’s electronic surveillance have raised alarms about privacy. Today's Wall Street Journal reports that the National Security Agency’s capacity is even broader than has reported before—enabling it to reach " roughly 75% of all US Internet traffic."Is there any way to use the Internet secretly? Yes, there is. It's the Darknet, available through software that allows anonymous browsing—and, increasingly—provides opportunities for organized crime. On Silk Road, for example, customers can find LSD, cocaine and heroin as if they were shopping on Amazon — anonymously. Why hasn't the government cracked down? Are there legitimate reasons for Internet users to conceal their identities?