Mail Systems:
(Market Share) - June 2015

Web based mail clients
- gmail (Google) (16%)
- Yahoo Mail (4%)
- AOL (1%)

Mail clients for your mobile device or personal computer:
- Apple iCloud, iPhone, iPad Mail (28%)
- Apple Mac Mail (8%)
- Google Android (9%) (may transition to gmail app)
- Microsoft Outlook 2007, 2010 (8%)
- Microsoft Outlook-com (4%)
  Office 365 Mail appears to be the same.
- Windows Live Mail (WLM) (2%)
  (Successor to Outlook Express on Windows XP and Windows Mail on Windows Vista.)
- Windows Hotmail (now outlook)
- Microsoft Exchange
- Thunderbird
- Pegasus
- Eudora - Discontinued - Last release was 2010

Mail overview:
There are two parts to an email system.

  • Mail Server - Usually a web hosting service for the domain where you have your email sent. e.g.
  • Mail Client - Where your read your mail. e.g. Outlook Express, Mac Mail, Eudora...
Cloud base email services like gmail, yahoo mail, hotmail, serve both functions.
  1. There are basically two ways to handle reading and storing your email.
  2. A cloud based email program link gmail, yahoo mail, hotmail, ...
  3. A mail client that runs on your PC. e.g. Outook express, Windows Live, Thunderbird, Eudora, Mac Mail, ...
    These require you set up a protocol for communicating with the server.
Special situations:
a winmail.dat file sometimes shows up as an attachment in mail sent via Outlook on Windows computers.

Unfortunately, Outlook does not "play nice" with the other email programs all the time. This causes problems, not for the sender of the email, but the recipient, particularly when actual files are attached to messages.

When an Outlook user composes and sends a message using either Rich Text Format or HTML Format, Outlook automagically generates a file, winmail.dat, and attaches it to the end of the message. winmail.dat contains formatting information, in a human-unreadable form, that Outlook will use on the receiving end to display this email message correctly. Unfortunately, Outlook is the ONLY email client program that can use this information! Netscape Messenger, Eudora*, and other email client programs don't understand this information.

Theoretically winmail.dat could also contain attachments, but myexperience has been that if other attachments (e.g. word documents, pictures) are included, they show up individually not in a winmail.dat file.

How to avoid sending winmail.dat:
If you are sending messages to a mailing list or as a group mailing, you MUST set ALL users up so that they receive plain text email. If even one user is set up in your address book, or your default setting is to receive Rich Text Format or HTML format email, everyone will receive that format.

If you enter the recipient's address manually in the To: line of your email message, you must choose Format->Plain Text from the menu bar or change the default to plain text in Tools -> Options.

There are several programs that allow you to decode winmail.dat
For Windows:
WWMdecode at

For Mac:

Address Format:
An email address such as is made up of a local part, an @ symbol, then a domain part.

Dots and capitalization doesn't matter in gmail. = =

Multiple Addresses:
Separate by a comma.
To:, Ted , Ina Mako 

Outlook and other email programs that look for first and last names to be separated
by commas may run into problems if you separate email recipients with commas, too. 
So, use a semicolon,
To:; Ted ; Mako, Ina 

How to Separate Multiple Recipients Correctly - About Email
Receiving someone else's mail - Gmail Help

Email Client Market Share and Popularity -
Email Ettiquette
Fraud, Scams
Email Tech Notes
Why (and how) I'm saying goodbye to Gmail | Macworld

last updated 22 July 2015