16. The system of claim 15 , further comprising a portable power source, a touchscreen, and a housing for carrying the processor, memory, power source and touchscreen, wherein the system is sized to be handheld or worn by a user, and wherein the processor is coupled among the memory, power source and touchscreen.
18. The system of claim 16 , wherein the user-input set of text is part of a text message entered by a user into a messaging application, and wherein the digit formatting module is further configured to: identify one or more keywords within a previous message received by the messaging application; and modify the unformatted digit string into the formatted digit string based on the identified one or more keywords within the previous message.