Back in the day, when bad guys used telephones, the FBI and other law enforcement agencies would listen in with wiretaps. As long as phone companies cooperated—and they had to, by law—it was a relatively straightforward process. The Internet, however, separated providers of communications services—Skype, Facebook, Gmail—from those running the underlying infrastructure. Thus, even if the FBI obtains a suspect's traffic data from their Internet service provider (ISP)—Comcast, Verizon, etc.—it may be difficult to make sense of it, especially if the suspect has been using encrypted services.