Contents: Salutations | Line Length | Attachments | Format | Subject line Abbreviations | Web links | Discretion - Careful what you say | Terms/Abbreviations/Emoticons

Email Netiquette

Salutations

I've noticed a lot emails I've got recently start with "Hi Don,"
or "Hello," when addressed to multiple people.

I did a google search on email salutations and couldn't find any consistent guidelines.

Kaitlin Duck Sherwood says: I usually use a simple "Hi" for people that I already know:
  "Hi - Are you interested in getting together for sushi next week?"

Do We Have to Use Email Salutations?
LegalAndrew says no.

See:
A Beginner's Guide to Effective Email - Greetings and Signatures

Check authenticity before Forwarding email

Look up your message in some of the links at the Hoaxes page before forwarding email which asks you to send it to all your friends.

Line length

Set your email client's automatic word wrapping feature to something between 65 and 75 characters to make sure your messages do look good in every email program on every computer.
Note: It's better to let your mail program wrap than to try and type returns yourself. If you type your own returns at the end of lines and make tham longer than your default line length you will end up with a choppy text with alternating long and short lines.
e.g. If you type:

  Now is the time for all good people to come to the aid of their country.<RETURN>
  A second line after hitting the return key.

Your message will end up like:

Now is the time for all good people to come to the aid of their
country.
A second line after hitting the return key.

see email.about.com/cs/NetiquetteTips

Attachments

Attachments are great for sending things other than text or html. E.g. Word processing documents, spread sheets, pictures, songs, compressed collections of files (.zip)... However, the recipient must have program and correct version to open them, so agree with the recipient about the format of an attachment before you send it.
E.g. some Dell computers shipping in 2004 had Word Perfect instead of MS Office.
Attachments also cause extra steps of download and opening another program to view them, which take up bandwidth, disk space and processing time.
There are size limitation on attachments depending on the mail server you are using (e.g. hotmail, yahoo, comcast, aol, ...)

Here are some tips to consider before attaching a document.

• Title the document that you are attaching in a way that is easy for the recipient to find once he or she downloads it to his or her files. For example, if you are sending a document that is a goal statement then title it "goalstatement.doc."
• In the content of your email, tell your recipient what type of software was used to create the document, the year/version, and the title of the attachment. For example: "The file attached is called "goalstatement.doc" and it is in MSWord 2000."
• Make sure that you do not send overly large attachments unless you are sure that your recipient's Internet connection and email client can handle them. For example, a user on a 56K dialup would have to spend a long time downloading a 5M PowerPoint file, whereas a co-worker on a fast work connection would have no problem.
• Don't send unnecessary attachments -- if you've already presented all of the relevant information in an email message, don't attach a Word document repeating the same information

Format - Plain Text vs HTML

Some email programs are not capable of rendering the HTML used for rich formatting in email messages. Others try, but fail, rendering your message unaccessible to the recipient. When in doubt send plain text.

RE: Reply - Reply to a message - usually inserted by mail program
FW: Forward - A forwarded message
FYI: For your information
NRR: No reply required (same as FYI)
AR: Action Required
AB: Action by e.g. AB+2 Action by 2 days
RR: Reply Requested
FYA: For your action
URG: Urgent 
ACTION: (Air Force Guidance Memorandum - 9 Nov. 2011)
WAS: Old topic changed. e.g., 
"Re: What is the best kind of teapot? (WAS: What is the correct temp. for brewing tea?)"
NWS: Not Work Safe - Adult content - Don't open at work or when kids are around.
         Same as NSFW - not safe (or suitable) for work or "ADLT:"
         The FTC requires "SEXUALLY-EXPLICIT:"

The following are suggestions which are sub categories of FYI:
Humor: Jokes and things like "You know you're getting old if ..."
Cute: Emails with someones beautiful pictures, video links, etc.
WIS: Wisdom - How to save your marriage, How to deal with a liberal/conservative, ...
POL: Politics
REL: Religion

Others:
ADV: Advertising - Proposed by the FTC's "Subject Line Labeling As
       A  Weapon Against Spam"

• Thou shalt include a clear and specific subject line.
• Thou shalt edit any quoted text down to the minimum thou needest.
• Thou shalt read thine own message thrice before thou sendest it.
• Thou shalt ponder how thy recipient might react to thy message.
• Thou shalt check thy spelling and thy grammar.
• Thou shalt not curse, flame, spam or USE ALL CAPS.
• Thou shalt not forward any chain letter or virus warning.
• Thou shalt not use e-mail for any illegal or unethical purpose.
• Thou shalt not rely on the privacy of e-mail, especially from work.
• When in doubt, thou shalt save thy message overnight and reread it in the light of the dawn.

Thanks:
If the only thing you have to say is "Thanks" most people do not reply at all to avoid email overload.

Terms/Abbreviations/Emoticons:

AFAIK	As far as I know
BRB	Be Right Back
BTW	Buy the way
DQMOT	Don't Quote Me on This
EOM	End of Message (same as SIM)
FWIW	For What It's Worth
FYI	For Your Information
IMHO	In my humble (or honest) opinion
IMO	In My Opinion
LMAO	Laughing my a** off
LOL	Laugh out loud
NRN	No Reply Necessary
NT or N/T	No text (same as SIM or EOM)
SIM	Subject is message (same as NT or EOM)
TIA	Thanks in advance
TTFN	Ta ta for now
:-)	smiling and generally happy
:-|	indifferent and generally indifferent
:-(	frowning and generally unhappy
;-)	winking and generally witty

Others at Abbreviations under Web stuff.