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Subject: INV5006687.pdf

This week I received an email with the subject "INV5006687.pdf." It came from someone I do not know at a company whose name I didn’t recognize, and it included an attachment. It stood out as junk, a message to delete. But as my right pinkie stretched to the Delete key, something told me to take a peek. I did.

To my surprise, INV5006687.pdf was not spam. The message had been sent by a company I know by another name. Attached was a PDF of an invoice for a classroom I had recently rented.

On business letters, it is acceptable to include a purchase order number or invoice number as a subject, introduced by the abbreviation Subj. or Re. But that doesn’t work in email–not with spam bouncing off the filters of companies everywhere. It definitely does not work when the reader doesn’t know the sender.

I would have recognized this subject immediately:

Invoice for Your Classroom Rental on November 28

Moral of the story: If you are sending an invoice by email, do not use the invoice number as a subject–not if you want payment. Only by pure luck will your reader hesitate before pressing Delete.


Posted by Lynn Gaertner Johnson
By Lynn Gaertner-Johnston

Lynn Gaertner-Johnston has helped thousands of employees and managers improve their business writing skills and confidence through her company, Syntax Training. In her corporate training career of more than 20 years, she has worked with executives, engineers, scientists, sales staff, and many other professionals, helping them get their messages across with clarity and tact.

A gifted teacher, Lynn has led writing classes at more than 100 companies and organizations such as MasterCard, Microsoft, Boeing, Nintendo, REI, AARP, Ledcor, and Kaiser Permanente. Near her home in Seattle, Washington, she has taught managerial communications in the MBA programs of the University of Washington and UW Bothell. She has created a communications course, Business Writing That Builds Relationships, and provides the curriculum at no cost to college instructors.

A recognized expert in business writing etiquette, Lynn has been quoted in "The Wall Street Journal," "The Atlantic," "Vanity Fair," and other media.

Lynn sharpened her business writing skills at the University of Notre Dame, where she earned a master's degree in communication, and at Bradley University, with a bachelor's degree in English. She grew up in suburban Chicago, Illinois.

2 comments on “Subject: INV5006687.pdf”

  • Hi,

    One of the reasons for such kind of subject is windows. Typically, a company shall store it’s documents with invoice number etc. Now, if the company needs to send the document to you, it just right clicks on the document and selects the option ‘send INV5006687.pdf as email’. I am assuming that the company is using Microsoft Windows and Microsoft Outlook features.

  • Chakshu, thanks for pointing out what happened. I had forgotten about that feature. So to communicate clearly, the person sending the email needs to take the time to change the subject.

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