Voice messages, particularly in local dialects, are safer than text messages, which can be monitored by Chinese security agents.
"In the conventional model of marketing we are fed messages, which can come through advertising channels, they can come through digital channels.
Telegram is an app that allows people to talk using encrypted messages, which can only be read by the two people receiving them.
The transportation authority currently sends out regular e-mail messages — which can also be sent to cellphones — to commuters about track work and other planned service disruptions.
Each stage has a hidden "stamp" to find, which can then be used to illustrate notes and messages, which can be pinned to levels for other players to read.
They stay in touch through cellphones, e-mail (the Internet is still tightly controlled, but some Cubans use connections at universities and cybercafes in hotels) and even text messages (which can be routed through a third country).
One of the students involved, Zosh Skowronska, said: "The letter being taken seriously and going viral has only helped the delivery of the police's crime prevention message, which can only be a good thing".
With eight megabytes of built-in memory, the Olympus DS-150 digital recorder can store up to 1 hour and 40 minutes of conversation then organize it into 99 different messages, which can be downloaded to a personal computer.
His message, which can be summed up as "Don't trust them," was repeated on Nov. 24 in a more formal setting when Mr. Clohessy spoke to a plenary session of the American Academy of Religion, the academic association for scholars of religion.
