Recently I completed a managed send for a daily voucher codes client. I can’t specify the product names or the client in this blog so what I’ll say is that they had three deals in the subject line: tablets, handbags and geek t-shirts.

The send

We tried four subjects with the deals in a different order each time and in one case, just one of the items – perhaps what we deemed to be the most desirable:

1. Tablets, handbags, t-shirts

2. Handbags, tablets, t-shirts

3. Tablets

4. Tablets, handbags

The results

Our subject line selector found that number 4, with ‘Tablets’ first and ‘Handbags’ second, won after two hours and this subject was used for what remained of the list.

We believe this is due to tablets always being popular for mainly the men but also some women and of course the handbags being almost all women, so with this subject line the client was appealing to two main audience demographics.

The other two subject lines, which were longer and mentioned the t-shirts, got the same percent of opens as each other just not as much as the one mentioning only the tablet and handbags. There is a chance they were chopped short by some inbox’s or were simply too long for people to make the effort to read in comparison to the shorter subject line.

The subject about tablets alone was by far the least popular. Whilst often being short and punchy is good and can give the pre-header plenty of room, it is easy to believe that this alienated anyone not in the market for a tablet (or the specific item you are mentioning in your subject line). So what can we learn from this send?

1) Consider your subject line length

It has been a general rule of thumb to keep the subject line to 50 characters or less. You can always try out longer but informative text, if it is compelling, of interest to the demographic and satisfies the ‘what’s in it for me’ imperative it’s worth a test. You can always adjust for future campaigns once the metrics are analysed.

2) Testing

Too often subject lines are added as a last minute exercise. Firm up your subject lines as soon as you can so that you are ready for pre-testing to a seed list, especially important if you are using multiple subject lines. Use tools such as subject line selector whenever possible.

3) Use pre-headers

A pre-header should be given the safe care and attention as a subject line as it can help to further explain and enhance the power of it.

4) Support the ‘from’ line

Readers often look at the ‘from’ line first when deciding whether to open an email, and then the subject line. The ‘from’ line tells the recipient who sent the email, and the subject line persuades the recipient into opening. If your ‘from’ line lists your company name, you don’t have to repeat it in the subject line, which frees up space in the subject line. If you’re sending a regular newsletter give it a memorable name and put that in the subject line, people like continuity.

5) List your key information first

Some email clients allow more characters in a subject line than others, but most give you at least 50, including spaces, so load your key information at the start of that first 50. Also, make sure the cut-off doesn’t occur in the middle of a crucial word, such as a price or date.

6) Urgency drives action

Try setting a deadline: ‘Order by midnight tonight;’ ‘Last day to ensure Xmas delivery.’ Use urgency and deadlines as part of a planned series of emails as well. For example on Monday incorporate ‘5 Days Left…’ and then on Thursday follow it with ‘Only 24 Hours.’

7) Watch those spam filters

There’s a fine line between catchy and spammy. Run your email copy through a spam checker to identify any spam-like words, phrases or textual contortions. The spam checker should tell you which phrases to avoid. Two common errors that trip spam filters: email subject lines with all capital letters and using loads of exclamation marks. We recommend against using exclamation marks at all if you can avoid it (the emails above have done well to get into the inbox!)

8) Review subject-line performance

See which email subject lines delivered the action you wanted – the most website conversions, the highest number of leads generated, the highest click-through rates. This analysis could even help drive content and product selection strategies, but it can also show you what information is most relevant or useful so future subject lines can be adjusted to suit.