Consumer confidence has now edged up to a four-month high, but households are still downbeat about the economic outlook with inflation following last year’s Brexit vote. With consumers cautious about their spending, marketers need to be wary of simply ‘keeping the wheel turning’ and start thinking more creatively and strategically about how to really drive engagement.

There is a great challenge for marketers to ensure that their email outreach isn’t ending up in the spam folder when building rapport with customers. Emails that are generated by bots and sent in bulk are not creative and while internet service providers (ISPs) and email service providers (ESPs) are constantly adapting in order to outsmart email users to bypass spam alarms, not enough is being done by marketers to ensure this isn’t happening to their emails.  

ISPs have got inherently smarter over the past few years and they have moved away from more traditional spam alarms. The focus is now on user engagement and how the receiver interacts with the messages that arrive in their inboxes. This determines whether an email will go into the spam folder or safely into the inbox and at Mailjet we have analysed these patterns to discover what subject line language can cause this.

Terms to avoid

Poor interaction from recipients with an email has a negative effect on sender’s reputation and in turn impacts the deliverability of future messages as ‘spammy’ words increase the chances of poor interaction.

How often do you receive an email with ‘free’ in the subject line? Is there really anything free in that email? Usually not. Therefore, you will just scroll past an email that has attempted to lure you to open the message, delete it or complain, and this will impact the sender’s future inbox placement.

Therefore, what are common words or phrases that marketers need to be avoiding to ensure they are not being mistaken as a spammer or phisher and getting relegated to the junk folder?


Marketers should stay away from ever using the word ‘invoice’ in a subject line. While this triggers the spam alarm, it is also a cyber crime favourite. Phishing emails often include the word ‘invoice’ to try and bait users into reading their email and often clicking on a phishing link that can easily lead to a hack.

Unfortunately, scammers will try and profit out of users carelessness and it also has repercussions for marketing emails.

Bank names

Scammers often try to impersonate banks and send emails closely following their formats and using their names to get users to believe they are legitimate. They often link back to mirrored sites that ask for personal details, meaning emails that include financial institutions names like ‘PayPal’, ‘MasterCard’ or ‘Visa’ often end up in the junk folder, so marketers should try to avoid including these sorts of details in emails.

Gifts or wins

Scammers are still using the ‘dear friend’ tactic to get into hundreds of thousands of people’s inboxes. Meaning if you use words such as ‘gift’, ‘present’, ‘lottery’ or ‘specially for you’, you are likely to end up missing the inbox altogether and wasting your outreach as these types of scams are quick and easy to send so are still very popular.

Urgency or desperation

We have all received at least one ‘damsel in distress’ or ‘urgent help’ email. A distant relative you didn’t know existed asking for you to send them money urgently to help them, or an affluent person from a far-away country offering you a big inheritance. Using wording that alludes to financial gain, borrowing money or transferring funds urgently will trip that spam alarm.

Have a look at your junk box now to see how many African princes/princesses want to transfer you a million dollars. Unless you have already got great rapport with the recipient, try to avoid directing them ‘quickly’ to ‘urgent’ sales.


Brand messages that contain words such as ‘casino’ or ‘deposit bonus’ risk heading into the spam folder. Gambling spammers often send out campaigns that promise a high return, free entry or double deposits and if it isn’t a website users recognise then it will probably go into the spam folder, affecting the deliverability of future messages that might include gambling references.

Ensuring engagement

Marketers should be ensuring data quality, selective targeting and proper sending cadence throughout all customer outreach, as these are the main keys to strong deliverability. However, as long as brands aren’t sending something highly offensive or inappropriate content, words alone won’t necessarily damage sender’s reputation, as long as they are included in the correct context.

If marketing teams work to target the right people rather than take a ‘spray and pray’ approach, with engaging content and at the right frequency, they should have no problem hitting the inbox.

However, if brands are in the process of building rapport with customers they must avoid the ‘spammy’ words that might affect deliverability. Marketers must get to a point where their recipient trusts the brand and is always keen to engage with email content. If they achieve this, they could probably get away with using every ‘spammy’ word on the list and their engagement metrics would still look great.