Because e-mail is easy to use and fast to send, it has become the dominant form of interoffice business communication in many companies. Some companies have e-mail policies that state appropriate use. If your company doesn't have an e-mail policy, adhering to the following guidelines will ensure suitable use of workplace e-mail.

Keep the tone of formality set by your company
Every organization is different, so it's a good idea to read e-mails from fellow coworkers to determine what is acceptable. Notice whether the language is formal or whether smiley faces :-) are used and follow suit. When in doubt, keep it formal. This also goes for sending e-mail to clients and customers outside the organization.

Keep in mind that E-mail is permanent
Most company e-mail is backed up and archived, and companies have the right to review employees' e-mails. Remember this before you write something that may embarrass you or your company if it were read by others.

Limit personal e-mails
Every business differs in policy when it comes to using workplace e-mail for personal business. In general, personal e-mail should not take up the bulk of your inbox, nor should it take a significant amount of your time at the office. Use your discretion.

From: Markel, Mike. Technical Communication. 6th ed. Boston: Bedford/St. Martin's, 2001.