A computer program that allows people to send messages to eachother .

A secret word / phrase that is used to gain admission to something

Representation of facial expression

Etiquette on the internet 

Transmission of messages over communications network

practice of modify or altering computer software and hardware to be outside the creators objective

unauthorized copying of some purchased software

 link from a hypertext file or document to another location or file, typically activated by clicking on a highlighted word or image on the screen.