Netiquette in forums, chats, email...

Etiquette in technology is the conduct that is socially acceptable in an online or digital situation. While etiquette is ingrained into culture, etiquette in technology is a fairly recent concept. The rules of etiquette that apply when communicating over the Internet or social networks or devices. An example is the terms of use of the website.
Netiquette (short for "network etiquette" or "Internet etiquette") is a set of social conventions that facilitate interaction over networks, ranging from Usenet and mailing lists to blogs and forums. However, like many Internet phenomena, the concept and its application remain in a state of flux, and vary from community to community. The points most strongly emphasized about USENET netiquette often include using simple electronic signatures, and avoiding multiposting, cross-posting, off-topic posting, hijacking a discussion thread, and other techniques used to minimize the effort required to read a post or a thread. Similarly, some Usenet guidelines call for use of unabbreviated English while users of instant messaging protocols like SMS occasionally encourage just the opposite, bolstering use of SMS language. However, many online communities frown upon this practice.