How to start? Liz Danzico, the information architect and blogger at Bobulate, thinks that e-mail salutations have three basic purposes. In “Anatomy of a Salutation,”  she writes that salutations not only function as greetings, but set tone and establish a hierarchy between writers. More interesting, she notes that e-mail salutations evolve fairly quickly during back-and-forth correspondence. Most e-mail threads start out formal (“Dear Professor Miles”), but by the third e-mail the correspondents often drop to an informal “Hi,” or no greeting at all.

When writing a salutation, follow your correspondent’s cues. You’ll look stuffy and cold if you return a “Hey Charlie” with a “Dear Mr. Bowers,” and you could easily insult someone by using only their first  name. I like to check my correspondents signatures — if they sign only a first name, I can use only their first name, and if they sign their full name, I address them by their title and last name.

For more advice on writing business e-mail, check out E-Mail: A Write It Well Guide.