Message Formats

After you choose your message editor, you must choose your message format. The message format is the actual file format used to transmit the message. Outlook has three message formats you can choose from: HTML, rich text, and plain text. In Outlook 2003, the default mail format is HTML.

HTML Versus Rich Text Format Versus Plain Text

The differences between the three message formats are best illustrated in a table. Table 18.1 explains the differences in the three available message formats.

Table 18.1. Message Formats

Message Format	Description
HTML	Hypertext Markup Language format enables you to create highly formatted messages with embedded pictures and hyperlinks. HTML format is Outlook's default format.
Rich Text	Rich text format (RTF) is currently readable only by Outlook and Eudora mail clients. RTF enables you to send highly formatted messages, but only to recipients within your Exchange organization or those using Eudora.
Plain Text	Plain text messages are readable by all clients. Text cannot be formatted and pictures cannot be embedded. However, all mail clients can understand plain text.

You can use each of the available mail formats whether you're using WordMail or the native Outlook editor.

How Other Mail Clients Interpret Mail Sent from Outlook

Previous versions of Outlook defaulted to rich text format. This caused numerous problems with Internet email messages. Non-Outlook clients cannot interpret rich text formatting information. That information (along with attachment information) was encapsulated into a file, usually called Winmail.dat, and transmitted with the message. Any attachments sent with the message usually weren't received by the end recipient. Instead, the attachments were converted into information stored in the Winmail.dat file. You can still choose to use rich text format to compose your email messages, but doing so is recommended only in an Exchange environment when you'll primarily be sending messages to other Exchange recipients. Each message format has an effect on how your recipients will see your Outlook message. The following list illustrates how recipients will receive each type of Outlook message:

• HTML Format Selecting HTML as your message format enables you to use backgrounds, embed pictures and multimedia, and utilize all other types of HTML formatting. HTML format is the most capable format, but it's also the format of choice for transmission of several viruses. Because of this, many email administrators are blocking HTML mail at the email server, and many individuals are turning off the capability to display HTML emails. If you send an HTML email to someone who has disabled viewing of HTML email, the recipient will see only a plain text interpretation of your email with all the associated HTML code.

• Rich Text Format Rich text format can be understood by the least number of other email clients. When viewing messages sent over the Internet, even other Outlook clients often have problems with this format. If you send attachments in a rich text formatted email, those attachments will not usually be received. Instead, recipients will receive a file named Winmail.dat that contains all the rich text formatting information and attachment information that the email client could not understand.

• Plain Text Format Plain text format is the most universally understood email format. All mail clients can read messages sent in plain text format. Message sizes are generally significantly smaller than rich text or HTML formats because no formatting information is sent with the message.

Choose your> mail format based on the individuals you send messages to and the types of messages you send. Sending formatted newsletters often requires HTML format. Sending to users in your Exchange organization is best done with either HTML or rich text format. Sending messages that are universally viewable is best with plain text format.

After you choose a global mail format, you can still change the format on a message-by-message basis. With Word as your email editor, a drop-down list on the new message toolbar enables you to select HTML, rich text, or plain text. If you're using the native Outlook editor, you can select the Format menu and choose from Plain Text or HTML format. If your default message format is HTML and you want to switch to rich text, you'll need to first switch to plain text and then switch to rich text. You cannot directly switch from HTML to rich text. However, you can switch directly from plain text or rich text to either other format.