Best Practices in Writing Email Subject Lines
2007 Subject Line Comparisons
The best email subject lines are short, descriptive, and provide the
reader with a reason to explore your message further. Attempts to stand
out in the inbox by using splashy or cheesy phrases will invariably
result in your email being ignored. In short, the conclusion of
i-Emailer's second email subject line study echoes our previous study -
keep your subject lines simple and to the point.
For this study, i-Emailer analyzed the open rates for over 200
million emails. Open rates ranged from an amazing 93% to a dismal 0.5%.
Many additional factors affect how an email is viewed such as
frequency, sender, and the nature of the message. Personal messages are
at the top of the interest scale, followed by affiliations and timely
news. At the other end of the scale are stale newsletters, requests for
money and offers that are too good to be true.
Three Words to Avoid
An unexpected discovery in our analysis was the negative impact of three innocent words.
Email marketers are familiar with words such as "free" which are
generally to be avoided in emails since they tend to trigger spam
filters. We identified innocuous words that won't trigger a spam
filter, but will negatively affect your open rates. They are: Help,
Percent off, and Reminder. Read more about the three words to avoid in
email.
Localization Helps
Another finding: personalization such as including a recipient's first
name or last name does not significantly improve open rates. Providing
localization, such as including a city name, does help.
Newsletter Half Life
Newsletters tend to start with high open rates, but all experience some
reduction in time. The challenge to the newsletter writer is to keep
the content fresh. Repeating the exact same subject line for each
newsletter accelerates the drop in open rates. While it is important to
establish continuity and branding of the newsletter, ideally each new
campaign should provide a clear indication in the subject line of what
is inside this newsletter that is of interest.
Subject Line Length
The general rule of thumb in email marketing is to keep your subject
line to 50 characters or less. Our analysis found this to generally be
the rule. The exception was for highly targeted audiences where the
reader apparently appreciated the additional information in the subject
line.
The From Line
The From information can be as important as the subject line. As a best
practice the From and Subject line should work in tandem. The From line
should communicate who you are as the sender. As much as possible this
entry should not change and should concisely convey who you are. Save
any humorous phrases or concepts for the subject line.
Promotional Emails
By their very nature, promotional emails tend to not perform as well as
emails where the reader has a high level of emotional affinity or
expects valuable and timely information. Within the category of
promotional emails, the same basic rules apply. Keep the message
straightforward and avoid using splashy promotional phrases, CAPS, or
exclamation marks in your subject lines. Subject lines framed as
questions can often perform better.
List Quality & Frequency
Two additional factors that are difficult to track but can have a big
impact on open rates are list quality and frequency. Email marketers
that build high-quality lists where readers know what they are going to
receive enjoy the best open rates. If you start with a good list but
send too frequently, open rates drop precipitously.
Best & Worst Subject Line Examples
Here's a comparison of email campaigns taken from the highest vs. the lowest open rate samples in our study.
Note: all names have been changed in the subject lines below.
| Subject Lines With Top Open Rates |
| Subject Line | Open Rate | Comment |
| Preliminary Floor Plans for Southern Village Neighborhood Circle Members |
93% |
Timely information. Implied benefit for quick action. Over 50 characters in length
|
| Your April Website Stats |
92.6% |
Timely and useful information |
| Idlewild Camp - Important Travel Information | 90.1% | Information I need now. |
| Invitation for Murdoch, Brown, Rove & Johnson's Snow Ball | 89.7 | Party invitation. Personal and timely |
| MotorCycling Magazine Reader Survey | 88.1% | High affinity to activity/experience |
| Announcing Paige Elizabeth Sullivan | 82.6% | Birth Announcement: Personal and useful information. |
| Ship's Log #5: Parus Arrives in Phuket | 82.1% | Personal and timely |
| Nautica in Rutland Opens Soon! | 79.9% | New condos - valuable information to be first in line. |
| Updated Time Zones & Log On Information | 79.1% | Required information |
| MICHAEL DRUCKMAN 1949-2007 | 77.4% | Obiturary: Personal |
| Inside Football: Summer Training Camp Preview Issue | 74.3% | Timely and useful information |
| Subject Lines With Low Open Rates |
| Subject Line | Open Rate | Comment |
| Final reminder for complimentary entry to attend the West Freelands BCI Cluster Conference 2006 | 0.5% | Reminder and subject is too long |
| Tempting August NUSA Specials! | 0.9% | Special. Exclamation mark |
| SALE ends soon - up to 50% off all bras at Kara! | 1.9% | Percent Off |
| Help Baylor create the ideal college experience | 2.5% | Help - means ignore |
| Printers World Offers 100% Commission Up Front | 7.5% | Too good to be true |
| 3% Commission For You, $10,000 in Upgrades For Your Client | 7.8% | Bait & Switch |
| Help Spread The News ! | 10.8% | Help |
| Don't Let 2006 Slip Away Without a Tax Deductible Donation To the Children & Families of Omire | 11.6% | Donation and too long |
Reduce Opens with Repeating/Reminder Subject Lines
It's obvious that if you send the same campaign over and over again
(such as reminders for an event), your open rates will decline with
each subsequent campaign. But just how much should you expect it to
decline? We found one example in our study of a user sending event
reminders to his list:
| Subject Line | Open Rate | Comment |
| Funk n Sandi @ The Roxy on 3 March | 8% | First Email |
| Funk 'n' Sandi @ The Roxy on 3 March | 6.3% | Second Email |
| This Sat 3 Feb - Funk n Sandi @ The Roxy | 5.1% | Third Email |
| Don't forget - Funk 'n' Sandi this Sat 3 Mar! | 3.5% | Fourth Email |
Takewaways
Put yourself in your recipients' shoes. People are flooded with spam
and increasingly pressed for time. Vague teasers, constant reminders,
and pleas for money are not going to cut through the inbox clutter. The
same advice we gave in our 2006 subject line comparison study remains true. When it comes to subject lines, don't sell what's inside. Tell what's inside.
Other Useful Resources:
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