Netiquette: The written or unwritten rules of etiquette that govern online interaction between users on the Internet. Note: Some typical rules are a ban on profane or offensive language, a requirement to respect other users, and a ban on floods of unsolicited advertisements. (As prepared by ATIS Committee T1A1.)
A Simpler Explanation: Using technology to communicate with others with understanding, respect and courtesy. It applies to personal, professional and educational communications.