Netiquette is network etiquette, conventions for behavior and courtesy while using the Internet. When using the Internet, we shouldn't SHOUT, send SPAM or FLAME.
Shouting is typing messages in ALL CAPS. Email typed in all caps is difficult to read, and any intended emphasis is lost, so shouting is considered bad form on the Internet.
Spam is considered to be garbage or off-topic Email messages posted to newsgroups, usually with multiple messages being sent. The Internet equivalent of junk mail, this is considered very inappropriate.
The term Flame refers to sending an insulting Email message to a person or a newsgroup. Flaming someone is not nice, and if an argument gets out of hand it can cause a Flamewar.