Inbox Bound: 'Hooky' Subject Line Tips

Inbox Bound: 'Hooky' Subject Line Tips

In Part 3 of our Inbox Bound series focusing on email marketing techniques, we cover essential tips on how to 'hook in' your email recipients through effective subject lines.

Over the past few weeks we have looked at various email marketing tips, focusing on how to avoid automated spam filtering and how to prevent recipients from knowingly marking you as junk. In Part 3 of our Inbox Bound series we focus on subject lines, and how this tiny part of your email can have a major impact on your marketing campaign's success.

Recent statistics show that almost half of email recipients (47%) are drawn to opening an email due to the subject line alone. Only 26% clicked on an email because of a special offer. So it's certainly worth investing a little time on your subject lines.

Tell, Don't Sell

Email platform MailChimp analysed the best and worst performing subject lines from over 40 million emails sent through its system. In short, it found that "boring works best". Surprisingly, subject lines containing discounts or offers didn't necessarily perform well, but those with straightforward content such as "Company Update" achieved a high rate of clicks.

Key to this pattern is that the best performing newsletters don't go for the hard sell. Instead, they merely give a glimpse into the subject of the email. MailChimp recommends: "When it comes to email marketing, the best subject lines tell what's inside, and the worst subject lines sell what's inside." Senders can still advertise discounts, but it's much better to separate promotional emails from informative newsletters - rather than try to blend the two.


In its July 2012 report, Adestra found that some of the best performing subject lines contained news related terms such as "News", "Update", "Breaking", "Alert" and "Bulletin". It states that such terms saw better than average click-to-open rates with "Alert" drawing the highest rate of clicks, and "News" generating the most opens.

But beware of "Newsletter". This was the outsider and the only news-related term to perform below average.

The Long and Short of Subject Lines

There is plenty of debate about how long a subject line should be, and even the statistics seem to disagree with each other.

MailChimp claims that the best email subject lines are short, descriptive and provide the reader with a brief overview of the email content. Statistics from Informz 2012 Email Marketing Benchmarks Report show that subject lines with fewer than 10 characters were the most successful, with an open rate of 58%. But it says that subject lines with 50-59 characters were also acceptable. Adestra's July 2012 claimed that 'snappy' subject lines of 1-2 words easily performed the best, but also found that those with more than 14 words performed well.

The best approach is to adapt your subject line to your email content. If you have a lot to say, try to summarise your content but break your subject line wording into bite-size chunks, separated by punctuation. And if in doubt, stick to the golden mantra of "short, sharp and sweet".

Which subject lines encourage you to click? And which end up in your Spam folder?

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