On the Subject of Subject Lines

Subject line – the few words that stand between the success and failure of your email marketing. As your customer scans through his 100 odd emails over his morning coffee, you have milliseconds to convince him, to open, read, and engage. It is therefore sometimes surprising how such little thought and effort goes into the humble subject line. How do we ensure we are maximising the use of these few words?

If we accept that its principle purpose is to get an email opened, there are perhaps three main themes we can go with.

Apple Announces the New iPhone 5.”

A safe factual announcement, if you know where your reader’s interests lie, you are there. The traditional direct marketing approach has always been to push a clear benefit statement.

“Be the First to Experience True Luxury”

And teasers look to use intrigue and some excitement to entice people in.

“Inside, the Future of E-mail Marketing”

These are all tried and tested, the first two being the safer options. The challenge with a teaser is you may not always hit your mark unless you know your customers really well.


Testing on subject lines suggests that short lines get the opening rates, but longer ones achieve a better click-through. What we need to factor in here is that most email clients and ESPs will truncate the subject line that the reader actually sees, in extreme cases leaving you only three or four words to make your point, and get opened. We need to make sure we pack our key messages into the first few words, consider below.

“Read This Email to Find Out How You Can Travel First Class”

Could get truncated and become meaningless, even discouraging, whereas:

“First Class: Your Next Trip – Read How”

Ensures we get our key point across quickly. Note the use of the colon; helps structure non-sentences to work for you.


If you have a strong or familiar brand name, it may help to put it front and centre into the subject line. This is particularly where the customer has a relationship with that brand. Linking your name and the purpose of the email is practical, functional, and will likely get the job done:

“News and Offers From Cathay Pacific”

There are exceptions, for those brands unfortunate enough to have been hijacked by the darker elements of email marketing.

“Discount Gucci Handbags for Less”

Not only lacks credibility, but it will likely fall foul of the spam filters.

Ensuring that your brand name or company name is clearly displayed in your sender address will free up valuable space in the subject line, for more of those impactful words.


As a rule, we live by personalisation, and it works well in almost all forms of marketing, but generally not in the subject line.

“Stephen, You Must Read This E-mail”

Is classic spam fodder and may well get filtered. Such lines also lack creditability, they suggest an intimacy that just does not exist. Remember, truly personal emails almost never include a name in the subject line. Better to demonstrate your knowledge of the customer by customising the subject line.

“Amazon Recommends: Tom Clancy at Half Price”

Where sales tracking tells Amazon that he is my favourite author. That will get my attention.

Spam Filters

The spam filters work overtime keeping this stuff out of our mailbox. There are all the usual offenders.

Viagra…Discount Rolexes…Save $$$.

But even some more innocent words creep in.


There are plenty of online lists of common spam words and any good digital copywriter will know how to avoid them. But filter rules do change over time; you should always monitor your results for suspicious numbers. Anything odd, check your copy for anything out of the ordinary.

General Copy Points

A sense of urgency always works; perhaps be a little more subtle to avoid the spam filters. Understand your customers and write in a way that they will identify with and relate to. Referencing past interaction, current events, and areas of commonality can work well.

Critically, get your copy, including the subject line, written properly. There are plenty of talented, and sometimes starving, digital copywriters out there, grateful for the work. I don’t think there is anyone in the agency business that has not had to confront a client with their personally supplied and lovingly crafted, but dreadful copy.

In Summary

  • Get your point across quickly
  • Customise, not personalise
  • Your name is good, but even better is the sender’s name
  • Use an experienced digital copywriter
  • Listen to your email agency (if they propose a change, there is probably a reason)

Finally, test everything; run split tests and compare results. Over time you will build a knowledge base of what works best for your brand, your products, and your customers.

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