“What words should I avoid in my email subject line to ensure I get to the inbox?”
This is possibly one of the most frequently answered (if not asked) questions in email marketing. To prove the point we decided to do a quick search “how to avoid spam” + “subject lines”
Although we had a sense that we would get a large number of results back, even we were surprised to find that there were about 8550 results for the search! Most of the articles/blogs/sites/white papers are centred around avoiding specific words or phrases that can trigger some Spam filters, or start adding “Spam points” to emails sent out.
In addition to these words many of the experts also advise against using the word unsubscribe, quotation marks, dollar signs , exclamation marks, question marks (one even advises against using any punctuation marks at all), capital letters or – and this made us splutter – use a font size larger than 2!
In effect the advice to legitimate marketers who are promoting a competition, sale or great offer and know that words and symbols like free $, £, win, discount or offer work on TV, in store and every other channel they use; is DON’T! The hit on deliverability and reputation far outweighs any sales uplift you might get from using tried and tested promotional techniques.
But is this still true today?
Like the definition of soft bounces – which we have argued are in definite need of an overhaul we think that both spammers and ISP’s have moved on and that it is time we revisited the issue of “spammy” words and punctuation in your copy and subject lines.
We believe that if you have followed best practice in IP address authentication and reputation management, data collection (opt-in) and list management as well as HTML coding you can within reason use any commercially effective words within the subject line or body copy that you choose. We also recommend you make sure that post deployment, you track all metrics by domain as well to ensure early identification of any ISP specific problems.
In order to test this theory we used two decidedly “spammy”, but definitely relevant subject lines for the last issue of Email-Worx.
To begin with we deployed, two versions of Email-Worx with identical content but different, very “spammy” subject lines: As Email-Worx follows best practice in data and content and is hand coded, we hypothesised that the effect would be minimal.
Subject line A: When to use |: +;&! in your subject line?
Subject line B: It’s – the ; Great & Subject + Line : Separator ? Debate !!!
And the result?
As expected we found no problems with our results according to the standard reports provided by our ESP – in fact they were fractionally better than usual.
- Less than 1% hard and soft bounces
- Open rates and click rates as follows:
- 35% open rate for both messages
- 28% & 30% total click rate for A and B respectively
- 20% and 19% unique click rate for A and B respectively
- No major differences by ISP
But when we looked at the reports in the delivery monitoring tool provided by our ESP we got a completely different potentially, terrifying picture.
- Subject line A was received into the inbox of 45% of the test accounts; 0.28% of junk folders and missing in 54% of the accounts
- Subject line B was received into the inbox of 47% of the test accounts; 0.28% of junk folders and missing in 52% of the accounts
So which if these two measures was right? If the standard reports provided by the platform were accurate our inbox delivery rate was completely normal. If the third party inbox monitoring software provided by the ESP was right on a pro-rata basis our open and click rates would have been 70% and 60% respectively – nearly twice our average!
So we decided to see what would happen if we ran the emails through a spam checker; and the result?
- Subject line A passed 89% of spam filters
- Subject line B passed 100% of spam filters
Curiouser and curiouser!
Finally we decided to ask YOU – the recipients; we sent out a quick survey asking the following questions:
- Did you receive the last issue of Email-Worx?
- Do you have Email-Worx sender address on a safe list or in your address book?
- If you received it in your junk folder what did you do?
- What platform (Outlook, Yahoo, macmail etc.) do you receive Email-Worx in?
- How often do you check your junk folder?
We had a survey completion rate of 8% and everyone who completed the survey has already been sent the full results as a thank you.
As you can see from the above chart the respondents engagement with Email-Worx ranged from the 25% who have only opened between 1 and 5 issues to the one or 2 people who have open over 50 issues! Here are a couple of interesting stats from the survey:
- 87% of respondents received their message in their inbox
- None of the recipients using a web based email client received the message in their junk folder.
We found the last stat very interesting indeed, the ISP’s (the people we worry about most) don’t seem to be paying any attention to subject lines at all!
So there you have it, the worrying results presented by the inbox delivery monitoring tool used by our ESP have been pretty much contradicted by all the other data we looked at, including the data provided by the spam checking tool which seemed to indicate that subject line A would get past almost 90% of spam filters and subject line B would get past 100% of spam filters. Before you ask, the spam checker and the inbox monitoring services we used were from the same company.
At this stage we are not drawing any conclusions – just reporting what happened when we investigated one email, but the result does raise some very interesting questions and we have been running a series of tests to try to answer the following questions and think you will be very interested in some of our findings:
- What has the most impact on inbox delivery – sender reputation; body copy; subject line; message size; images?
- Do all ISPs react in the same way as each other?
- Do ISPs always handle received messages in a consistent manner?
- How does the delivery monitoring software out there compare?
Without giving too much away before our findings are complete, we think that our results will challenge the way you perceive deliverability and junk mail filtering. We’ll be publishing the results in upcoming issues of Email-Worx, so let us know if you any comments on our recent experiment, or any particular concerns about email deliverabilty that you would like us to address.
Typical list of spam words:
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