Familiarity with a recipient determines whether an informal or formal salutation is appropriate. The format also affects this decision. Memos normally do not include a salutation, but recipients are identified in the heading. Email tends to be less formal in style.
When writing to a peer or to someone known on a first-name basis, an informal style may be used. These include first names or nicknames. Avoid slang, obscenity, or inappropriate attempts at humor in all forms of business communication. For example, “Hey dude” is not an appropriate salutation for any message exchanged within a business setting.
The most popular beginning to a salutation is use of the word “Dear.” This is followed ...