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Keep your subject lines short: use fewer than 50 characters.
In addition to reading your subject lines, many of your contacts are reading the opening lines of your emails when they
check their inboxes. This is because many email clients display previews of what's inside your emails right next to your
subject lines.
From a marketing perspective, this preview text presents a great opportunity to extend or elaborate on the messaging
of your subject line. When crafting your email, put this short line of text at the very top (above your greeting) to ensure
that it's the first thing the email client previews. A popular approach is to phrase the subject line as a question (e.g.
Ready for the big event?) and then answer that question with preview text (e.g. Our annual Inbound conference is right
around the corner … ).
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Lengthy subject lines get cut off, especially when people view their email on mobile devices. By using concise subject
lines (we recommend using fewer than 50 characters), you can ensure that your contacts can always read your subject
lines in full.
Align your subject line with your preview text.
Subject Lines
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Even if you uncover a "magic formula" for boosting email open rates — like framing your subject lines as questions and
answering them with preview text — be careful that you don't turn into a one-trick pony. Using the same subject
line configuration over and over again will likely yield you diminishing returns (i.e. lower and lower open rates each
time) as readers become bored or irritated by your repetitive messaging. So, to recap: test, test, and test some more.
Continually A/B test subject line messaging.
