This reference is a bit out of date but has a lot of good basic info.
The following is a condensed version:
This document provides a minimum set of guidelines for Network Etiquette (Netiquette) which organizations may take and adapt for their own use. As such, it is deliberately written in a bulleted format to make adaptation easier and to make any particular item easy (or easier) to find. It also functions as a minimum set of guidelines for individuals, both users and administrators. This memo is the product of the Responsible Use of the Network (RUN) Working Group of the IETF.
In the past, the population of people using the Internet had "grown up" with the Internet, were technically minded, and understood the nature of the transport and the protocols. Today, the community of Internet users includes people who are new to the environment. These "Newbies" are unfamiliar with the culture and don't need to know about transport and protocols. In order to bring these new users into the Internet culture quickly, this Guide offers a minimum set of behaviors which organizations and individuals may take and adapt for their own use. Individuals should be aware that no matter who supplies their Internet access, be it an Internet Service Provider through a private account, or a student account at a University, or an account through a corporation, that those organizations have regulations about ownership of mail and files, about what is proper to post or send, and how to present yourself. Be sure to check with the local authority for specific guidelines.
We've organized this material into three sections: One-to-one communication, which includes mail and talk; One-to-many communications, which includes mailing lists and NetNews; and Information Services, which includes ftp, WWW, Wais, Gopher, MUDs and MOOs. Finally, we have a Selected Bibliography, which may be used for reference.
2.0 One-to-One Communication (electronic mail, talk)
We define one-to-one communications as those in which a person is communicating with another person as if face-to-face: a dialog. In general, rules of common courtesy for interaction with people should be in force for any situation and on the Internet it's doubly important where, for example, body language and tone of voice must be inferred. For more information on Netiquette for communicating via electronic mail and talk, check references [1,23,25,27] in the Selected Bibliography.
2.1 User Guidelines
2.1.1 For mail:
- Unless you have your own Internet access through an Internet provider, be sure to check with your employer about ownership of electronic mail. Laws about the ownership of electronic mail vary from place to place.
- Unless you are using an encryption device (hardware or software), you should assume that mail on the Internet is not secure. Never put in a mail message anything you would not put on a postcard.
- Respect the copyright on material that you reproduce. Almost every country has copyright laws.
- If you are forwarding or re-posting a message you've received, do not change the wording. If the message was a personal message to you and you are re-posting to a group, you should ask permission first. You may shorten the message and quote only relevant parts, but be sure you give proper attribution.
- A good rule of thumb: Be conservative in what you send and liberal in what you receive. You should not send heated messages (we call these "flames") even if you are provoked. On the other hand, you shouldn't be surprised if you get flamed and it's prudent not to respond to flames.
- In general, it's a good idea to at least check all your mail subjects before responding to a message. Sometimes a person who asks you for help (or clarification) will send another message which effectively says "Never Mind". Also make sure that any message you respond to was directed to you. You might be cc:ed rather than the primary recipient.
- Be careful when addressing mail. There are addresses which may go to a group but the address looks like it is just one person. Know to whom you are sending.
- Watch cc's when replying. Don't continue to include people if the messages have become a 2-way conversation.
- Remember that people with whom you communicate are located across the globe. If you send a message to which you want an immediate response, the person receiving it might be at home asleep when it arrives. Give them a chance to wake up, come to work, and login before assuming the mail didn't arrive or that they don't care.
- Remember that the recipient is a human being whose culture, language, and humor have different points of reference from your own. Remember that date formats, measurements, and idioms may not travel well. Be especially careful with sarcasm.
- Use mixed case. UPPER CASE LOOKS AS IF YOU'RE SHOUTING.
- Use symbols for emphasis. That *is* what I meant. Use underscores for underlining. _War and Peace_ is my favorite book.
- Use smileys to indicate tone of voice, but use them sparingly. :-) is an example of a smiley (Look sideways). Don't assume that the inclusion of a smiley will make the recipient happy with what you say or wipe out an otherwise insulting comment.
- Wait overnight to send emotional responses to messages. If you have really strong feelings about a subject, indicate it via FLAME ON/OFF enclosures. For example: FLAME ON: This type of argument is not worth the bandwidth it takes to send it. It's illogical and poorly reasoned. The rest of the world agrees with me. FLAME OFF
- Be brief without being overly terse. When replying to a message, include enough original material to be understood but no more. It is extremely bad form to simply reply to a message by including all the previous message: edit out all the irrelevant material.
- Mail should have a subject heading which reflects the content of the message.
- If you include a signature keep it short. Rule of thumb is no longer than 4 lines. Remember that many people pay for connectivity by the minute, and the longer your message is, the more they pay.
- Just as mail (today) may not be private, mail (and news) are (today) subject to forgery and spoofing of various degrees of detectability. Apply common sense "reality checks" before assuming a message is valid.
- "Reasonable" expectations for conduct via e-mail depend on your relationship to a person and the context of the communication. Norms learned in a particular e-mail environment may not apply in general to your e-mail communication with people across the Internet. Be careful with slang or local acronyms.
2.1.2 For talk:
Talk is a set of protocols which allow two people to have an interactive dialogue via computer.
- Use mixed case and proper punctuation, as though you were typing a letter or sending mail.
- Use two CRs to indicate that you are done and the other person may start typing. (blank line).
- Always say goodbye, or some other farewell, and wait to see a farewell from the other person before killing the session. This is especially important when you are communicating with someone a long way away. Remember that your communication relies on both bandwidth (the size of the pipe) and latency (the speed of light).
- Remember that talk is an interruption to the other person. Only use as appropriate.
- The reasons for not getting a reply are many. Don't assume that everything is working correctly. Not all versions of talk are compatible.
- If left on its own, talk re-rings the recipient. Let it ring one or two times, then kill it.
- If a person doesn't respond you might try another tty. Use finger to determine which are open. If the person still doesn't respond, do not continue to send.
- Talk shows your typing ability. If you type slowly and make mistakes when typing it is often not worth the time of trying to correct, as the other person can usually see what you meant.
- Be careful if you have more than one talk session going!
3.0 One-to-Many Communication (Mailing Lists, NetNews)
- Any time you engage in One-to-Many communications, all the rules for
mail should also apply. After all, communicating with many people via one mail message or post is quite analogous to communicating with one person with the exception of possibly offending a great many more people than in one-to-one communication. Therefore, it's quite important to know as much as you can about the audience of your message.
3.1 User Guidelines
3.1.1 General Guidelines for mailing lists and NetNews
- Read both mailing lists and newsgroups for one to two months before you post anything. This helps you to get an understanding of the culture of the group.
- Do not blame the system administrator for the behavior of the system users.
- Consider that a large audience will see your posts. That may include your present or your next boss. Take care in what you write. Remember too, that mailing lists and Newsgroups are frequently archived, and that your words may be stored for a very long time in a place to which many people have access.
- Assume that individuals speak for themselves, and what they say does not represent their organization (unless stated explicitly).
- Remember that both mail and news take system resources. Pay attention to any specific rules covering their uses your organization may have.
- Messages and articles should be brief and to the point. Don't wander off-topic, don't ramble and don't send mail or post messages solely to point out other people's errors in typing or spelling. These, more than any other behavior, mark you as an immature beginner.
- Subject lines should follow the conventions of the group.
- Forgeries and spoofing are not approved behavior.
- Advertising is welcomed on some lists and Newsgroups, and abhorred on others! This is another example of knowing your audience before you post. Unsolicited advertising which is completely off-topic will most certainly guarantee that you get a lot of hate mail.
- If you are sending a reply to a message or a posting be sure you summarize the original at the top of the message, or include just enough text of the original to give a context. This will make sure readers understand when they start to read your response. Since NetNews, especially, is proliferated by distributing the postings from one host to another, it is possible to see a response to a message before seeing the original. Giving context helps everyone. But do not include the entire original!
- Again, be sure to have a signature which you attach to your message. This will guarantee that any peculiarities of mailers or newsreaders which strip header information will not delete the only reference in the message of how people may reach you.
- Be careful when you reply to messages or postings. Frequently replies are sent back to the address which originated the post - which in many cases is the address of a list or group! You may accidentally send a personal response to a great many people, embarrassing all involved. It's best to type in the address instead of relying on "reply."
- Delivery receipts, non-delivery notices, and vacation programs are neither totally standardized nor totally reliable across the range of systems connected to Internet mail. They are invasive when sent to mailing lists, and some people consider delivery receipts an invasion of privacy. In short, do not use them.
- If you find a personal message has gone to a list or group, send an apology to the person and to the group.
- If you should find yourself in a disagreement with one person, make your responses to each other via mail rather than continue to send messages to the list or the group. If you are debating a point on which the group might have some interest, you may summarize for them later.
- Don't get involved in flame wars. Neither post nor respond to incendiary material.
- Avoid sending messages or posting articles which are no more than gratuitous replies to replies.
- Be careful with monospacing fonts and diagrams. These will display differently on different systems, and with different mailers on the same system.
- There are Newsgroups and Mailing Lists which discuss topics of wide varieties of interests. These represent a diversity of lifestyles, religions, and cultures. Posting articles or sending messages to a group whose point of view is offensive to you simply to tell them they are offensive is not acceptable. Sexually and racially harassing messages may also have legal implications. There is software available to filter items you might find objectionable.
3.1.2 Mailing List Guidelines
There are several ways to find information about what mailing lists exist on the Internet and how to join them. Make sure you understand your organization's policy about joining these lists and posting to them. In general it is always better to check local resources first before trying to find information via the Internet. Nevertheless, there are a set of files posted periodically to news.answers which list the Internet mailing lists and how to subscribe to them. This is an invaluable resource for finding lists on any topic. See also references [9,13,15] in the Selected Bibliography.
- Send subscribe and unsubscribe messages to the appropriate address. Although some mailing list software is smart enough to catch these, not all can ferret these out. It is your responsibility to learn how the lists work, and to send the correct mail to the correct place. Although many many mailing lists adhere to the convention of having a "-request" alias for sending subscribe and unsubscribe messages, not all do. Be sure you know the conventions used by the lists to which you subscribe.
- Save the subscription messages for any lists you join. These usually tell you how to unsubscribe as well.
- In general, it's not possible to retrieve messages once you have sent them. Even your system administrator will not be able to get a message back once you have sent it. This means you must make sure you really want the message to go as you have written it.
- The auto-reply feature of many mailers is useful for in-house communication, but quite annoying when sent to entire mailing lists. Examine "Reply-To" addresses when replying to messages from lists. Most auto-replys will go to all members of the list.
- Don't send large files to mailing lists when Uniform Resource Locators (URLs) or pointers to ftp-able versions will do. If you want to send it as multiple files, be sure to follow the culture of the group. If you don't know what that is, ask.
- Consider unsubscribing or setting a "nomail" option (when it's available) when you cannot check your mail for an extended period.
- When sending a message to more than one mailing list, especially if the lists are closely related, apologize for cross-posting.
- If you ask a question, be sure to post a summary. When doing so, truly summarize rather than send a cumulation of the messages you receive.
- Some mailing lists are private. Do not send mail to these lists uninvited. Do not report mail from these lists to a wider audience.
- If you are caught in an argument, keep the discussion focused on issues rather than the personalities involved.
3.1.3 NetNews Guidelines
NetNews is a globally distributed system which allows people to communicate on topics of specific interest. It is divided into hierarchies, with the major divisions being: sci - science related discussions; comp - computer related discussions; news - for discussions which center around NetNews itself; rec - recreational activities; soc - social issues; talk - long-winded never-ending discussions; biz - business related postings; and alt - the alternate hierarchy. Alt is so named because creating an alt group does not go through the same process as creating a group in the other parts of the hierarchy. There are also regional hierarchies, hierarchies which are widely distributed such as Bionet, and your place of business may have its own groups as well. Recently, a "humanities" hierarchy was added, and as time goes on its likely more will be added. For longer discussions on News see references [2,8,22,23] in the Selected Bibliography.
- In NetNews parlance, "Posting" refers to posting a new article to a group, or responding to a post someone else has posted. "Cross-Posting" refers to posting a message to more than one group. If you introduce Cross-Posting to a group, or if you direct "Followup-To:" in the header of your posting, warn readers! Readers will usually assume that the message was posted to a specific group and that followups will go to that group. Headers change this behavior.
- Read all of a discussion in progress (we call this a thread) before posting replies. Avoid posting "Me Too" messages, where content is limited to agreement with previous posts. Content of a follow-up post should exceed quoted content.
- Send mail when an answer to a question is for one person only. Remember that News has global distribution and the whole world probably is NOT interested in a personal response. However, don't hesitate to post when something will be of general interest to the Newsgroup participants.
- Check the "Distribution" section of the header, but don't depend on it. Due to the complex method by which News is delivered, Distribution headers are unreliable. But, if you are posting something which will be of interest to a limited number or readers, use a distribution line that attempts to limit the distribution of your article to those people. For example, set the Distribution to be "nj" if you are posting an article that will be of interest only to New Jersey readers.
- If you feel an article will be of interest to more than one Newsgroup, be sure to CROSSPOST the article rather than individually post it to those groups. In general, probably only five-to-six groups will have similar enough interests to warrant this.
- Consider using Reference sources (Computer Manuals, Newspapers, help files) before posting a question. Asking a Newsgroup where answers are readily available elsewhere generates grumpy "RTFM" (read the fine manual - although a more vulgar meaning of the word beginning with "f" is usually implied) messages.
- Although there are Newsgroups which welcome advertising, in general it is considered nothing less than criminal to advertise off-topic products. Sending an advertisement to each and every group will pretty much guarantee your loss of connectivity.
- If you discover an error in your post, cancel it as soon as possible.
- DO NOT attempt to cancel any articles but your own. Contact your administrator if you don't know how to cancel your post, or if some other post, such as a chain letter, needs canceling.
- If you've posted something and don't see it immediately, don't assume it's failed and re-post it.
- Some groups permit (and some welcome) posts which in other circumstances would be considered to be in questionable taste. Still, there is no guarantee that all people reading the group will appreciate the material as much as you do. Use the Rotate utility (which rotates all the characters in your post by 13 positions in the alphabet) to avoid giving offense. The Rot13 utility for Unix is an example.
- In groups which discuss movies or books it is considered essential to mark posts which disclose significant content as "Spoilers". Put this word in your Subject: line. You may add blank lines to the beginning of your post to keep content out of sight, or you may Rotate it.
- Forging of news articles is generally censured. You can protect yourself from forgeries by using software which generates a manipulation detection "fingerprint", such as PGP (in the US).
- Postings via anonymous servers are accepted in some Newsgroups and disliked in others. Material which is inappropriate when posted under one's own name is still inappropriate when posted anonymously.
- Expect a slight delay in seeing your post when posting to a moderated group. The moderator may change your subject line to have your post conform to a particular thread.
- Don't get involved in flame wars. Neither post nor respond to incendiary material.
3.3 Moderator Guidelines
3.3.1 General Guidelines
- Make sure your Frequestly Asked Questions (FAQ) is posted at regular intervals. Include your guidelines for articles/messages. If you are not the FAQ maintainer, make sure they do so.
- Make sure you maintain a good welcome message, which contains subscribe and unsubscribe information.
- Newsgroups should have their charter/guidelines posted regularly.
- Keep mailing lists and Newsgroups up to date. Post messages in a timely fashion. Designate a substitute when you go on vacation or out of town.
4.1.2 Real Time Interactive Services Guidelines (MUDs MOOs IRC)
- As in other environments, it is wise to "listen" first to get to know the culture of the group.
- It's not necessary to greet everyone on a channel or room personally. Usually one "Hello" or the equivalent is enough. Using the automation features of your client to greet people is not acceptable behavior.
- Don't assume that people who you don't know will want to talk to you. If you feel compelled to send private messages to people you don't know, then be willing to accept gracefully the fact that they might be busy or simply not want to chat with you.
- Respect the guidelines of the group. Look for introductory materials for the group. These may be on a related ftp site.
- If a user is using a nickname alias or pseudonym, respect that user's desire for anonymity. Even if you and that person are close friends, it is more courteous to use his nickname. Do not use that person's real name online without permission.
5.0 Selected Bibliography
This bibliography was used to gather most of the information in the sections above as well as for general reference. Items not specifically found in these works were gathered from the IETF-RUN Working Group's experience.
- Angell, D., and B. Heslop, "The Elements of E-mail Style",New York: Addison-Wesley, 1994.
- "Answers to Frequently Asked Questions about Usenet" Original author: (Jerry Schwarz) Maintained by: (Mark Moraes) Archive-name: usenet-faq/part1
- Cerf, V., "Guidelines for Conduct on and Use of Internet", at: 
- Dern, D., "The Internet Guide for New Users", New York: McGraw-Hill, 1994.
- "Emily Postnews Answers Your Questions on Netiquette" Original author: (Brad Templeton) Maintained by: (Mark Moraes) Archive-name: emily-postnews/part1
- Gaffin, A., "Everybody's Guide to the Internet", Cambridge, Mass., MIT Press, 1994.
- "Guidelines for Responsible Use of the Internet" from the US house of Representatives gopher
- How to find the right place to post (FAQ) by (Aliza R. Panitz) Archive-name: finding-groups/general
- Hambridge, S., and J. Sedayao, "Horses and Barn Doors: Evolution of Corporate Guidelines for Internet Usage", LISA VII, Usenix, November 1-5, 1993, pp. 9-16
- Heslop, B., and D. Angell, "The Instant Internet guide : Hands-on Global Networking", Reading, Mass., Addison-Wesley, 1994.
- Horwitz, S., "Internet Etiquette Tips",
- Internet Activities Board, "Ethics and the Internet", RFC 1087, IAB, January 1989.
- Kehoe, B., "Zen and the Art of the Internet: A Beginner's Guide", Netiquette information is spread through the chapters of this work. 3rd ed. Englewood Cliffs, NJ., Prentice-Hall, 1994.
- Kochmer, J., "Internet Passport: NorthWestNet's Guide to our World Online", 4th ed. Bellevue, Wash., NorthWestNet, Northwest Academic Computing Consortium, 1993.
- Krol, Ed, "The Whole Internet: User's Guide and Catalog", Sebastopol, CA, O'Reilly & Associates, 1992.
- Lane, E. and C. Summerhill, "Internet Primer for Information Professionals: a basic guide to Internet networking technology", Westport, CT, Meckler, 1993.
- LaQuey, T., and J. Ryer, "The Internet Companion", Chapter 3 "Communicating with People", pp 41-74. Reading, MA, Addison-Wesley, 1993.
- Mandel, T., "Surfing the Wild Internet", SRI International Business Intelligence Program, Scan No. 2109. March, 1993.
- Martin, J., "There's Gold in them thar Networks! or Searching for Treasure in all the Wrong Places", FYI 10, RFC 1402, January 1993.
- Pioch, N., "A Short IRC Primer", Text conversion by Owe Rasmussen. Edition 1.1b, February 28, 1993. 
- Polly, J., "Surfing the Internet: an Introduction", Version 2.0.3. Revised May 15, 1993. [nysernet.org:70/00/ftp%20archives/pub/resources/guides/surfing.2.0.3.txt]
- "A Primer on How to Work With the Usenet Community" Original author: (Chuq Von Rospach) Maintained by: (Mark Moraes) Archive-name: usenet-primer/part1
- Rinaldi, A., "The Net: User Guidelines and Netiquette", September 3, 1992. 
- "Rules for posting to Usenet" Original author: (Gene Spafford) Maintained by: (Mark Moraes) Archive-name: posting-rules/part1
- Shea, V., "Netiquette", San Francisco: Albion Books, 1994?.
- Strangelove, M., with A. Bosley, "How to Advertise on the Internet", ISSN 1201-0758.
- Tenant, R., "Internet Basics", ERIC Clearinghouse of Information Resources, EDO-IR-92-7. September, 1992.
- Wiggins, R., "The Internet for everyone: a guide for users and providers", New York, McGraw-Hill, 1995.