Netiquette (neologism, a portmanteau formed from "Internet etiquette") is a catch-all term for the conventions of politeness recognised on Usenet, in mailing lists, and otheir electronic forums such as internet message boards. These conventions address group phenomena (such as flaming) with changes in personal behaviour, such as not posting in all uppercase, not (cross-)posting to inappropriate groups, refraining from commercial advertising outside the biz groups and not top-posting. RFC 1855 is a fairly lengthy and comprehensive set of such conventions.

The rules of netiquette are slightly different for newsgroups, web forums and IRC (Internet Relay Chat). For example, on Usenet it is conventional to write in standard English and not use abbreviations such as "u" for "you" or "ne1" for "anyone". These abbreviations are more likely to be tolerated on web forums, and are almost universal on IRC where, since discussion is real-time, they serve the practical purpose of speeding the flow of conversation. Many IRC users look down on this form of conversation, though. Issues such as the level of tolerance for off-topic discussion or spoilers may also vary from one newsgroup, forum, or channel to another. The rule of thumb in any of these discussion mediums is to "lurk before you leap"—get a feel for the local conventions before diving into conversation and inadvertently embarrassing oneself. Also, read the FAQ if there is one.

The following is a list of some of the more common rules associated with netiquette on Usenet.

• The most important rule of netiquette is, "Think before you post". If what you intend to post will not make a positive contribution to the newsgroup and be of interest to several readers, do not post it! Personal messages to one or two individuals should not be posted to newsgroups, use private e-mail instead.
  • This is sometimes stated in other forms, such as "Remember the human".

• When following up on an article, quote the minimum text necessary to give some context to your reply and be careful to attribute the quote to the correct person. If the article to which you are responding was cross-posted to several groups, edit the distribution ("Newsgroups:") header to contain only those groups which are appropriate to your reply, especially if the original message was posted to one or more inappropriate groups in the first place.

• Re-read and edit your posting carefully before you post. Check the spelling, grammar, and capitalization. Typing in all capital letters usually denotes screaming or yelling. Keep your lines to fewer than 70 characters. Do not post test messages except in their appropriate groups; wait until you have something to say. When posting humorous or sarcastic comments, it is conventional to append an emoticon, but do not overuse them.

• Before asking a question, read the messages already in the group and read the group's FAQ if it has one. When you do post a question, follow it with, "Please reply by mail and I will post a summary if requested," and make sure you do post a summary if requested; or, if only a few people were interested, send them a summary by mail. This avoids umpteen people posting the same answer to the group and umpteen others posting "me too"s.
  • However, many newsgroups follow the rule "Post here, read here" (that is, they explicitly discourage posters from requesting offline answers to topical questions). This is because there may be lurkers who would benefit from seeing the discussion unfold online, and because questioners often do forget to post summaries of their findings.

• Be proud of your postings, but do not post just to see your name in pixels. Remember: your future employer may be reading.

There is also a netiquette rule for how to deal with someone who has violated one of the rules of netiquette:

• If you believe someone has violated netiquette, send him or her a message by private e-mail; do not post a follow-up to the offending post. Be polite. The author may not have realized his or her mistake, may be a beginner, or may not even have been responsible for the "crime" — his or her account may have been used by someone else, or the address may have been forged. Furthermore, a person w0ho breaks netiquette over and over may be doing it intentionally to disrupt the group (see Internet troll), in which case public flaming over the violation would amount to what is termed feeding the troll.