This is the ability to send text messages to other devices (mobile phones, handheld). These are sent through a Short Message Service known as SMS, this service allows for users to write messages on a mobile device with a limit of 160 characters.
Text messages are very informal due to the fact that messages are composed on a smaller keyboard, texts usually contain abbreviated versions of words (i.e. U) or initials for a phrase (i.e. LOL, ROFL). Emoticons are also used to express emotions in the form of a small animation, like a smiling face or a heart.