¶ Cellphones, Though Banned, Thrive in U.S. Prisons (Kim Severson & Robbie Brown, The New York Times).

Although prison officials have long battled illegal cellphones, smartphones have changed the game. With Internet access, a prisoner can call up phone directories, maps and photographs for criminal purposes, corrections officials and prison security experts say. Gang violence and drug trafficking, they say, are increasingly being orchestrated online, allowing inmates to keep up criminal behavior even as they serve time.

“The smartphone is the most lethal weapon you can get inside a prison,” said Terry L. Bittner, director of security products with the ITT Corporation, one of a handful of companies that create cellphone-detection systems for prisons. “The smartphone is the equivalent of the old Swiss Army knife. You can do a lot of other things with it.”

“Almost everybody has a phone,” said Mike, 33, an inmate at Smith State Prison in Georgia who, like other prisoners interviewed for this article, asked that his full name not be used for fear of retaliation. “Almost every phone is a smartphone. Almost everybody with a smartphone has a Facebook.”