Two subject lines with identical wording can perform differently based purely on formatting choices — capitalization, length, punctuation, and how closely the format resembles a message from an actual friend versus an obvious mass marketing blast. These details get far less attention than the wording itself, despite meaningfully affecting open rates.
Why Format Signals "Genuine" or "Marketing" Before Content Does
A recipient's eye processes the visual shape of a subject line before fully reading its meaning, and certain formatting patterns — unusual capitalization, obvious promotional punctuation, excessive length — instantly signal "marketing email" in a way that triggers the same instinctive skip most people apply to obvious advertising. A subject line formatted more like a message from a real person tends to earn a beat of extra attention before being dismissed.
Formatting choices worth reviewing include:
- Avoiding unnecessary capitalization of every word, which reads as unnatural and overly formal
- Keeping length reasonable for how your specific audience's inbox displays subject lines
- Avoiding obvious spelling errors, which undermine credibility even if unintentional
- Considering whether your formatting resembles a genuine personal message or an obvious mass send
A Simple Framework
- Review your current subject lines for unnecessary or unnatural capitalization patterns
- Check how your subject lines actually display in common inboxes, since truncation varies
- Proofread carefully, since spelling errors in a subject line undermine trust before the email is even opened
- Compare your formatting against messages from people you'd actually consider personal correspondence
> Tip: Read your planned subject line next to a genuine message from a friend or colleague in your own inbox. If the formatting looks noticeably different — more capitalized, more punctuated, more "marketing" — that visual gap is exactly what triggers a recipient's instinct to skip past it.
Example
Before: A subject line formatted with unnecessary capitalization on every word and an excessive length that gets cut off awkwardly in most inboxes.
After: The same core message reformatted in natural sentence case, shortened to display fully, reading far more like a genuine message than an obvious marketing send.
Common Mistakes
- Using unnecessary capitalization patterns that read as unnatural or overly formal
- Writing subject lines too long to display fully in common inbox previews
- Overlooking spelling errors that undermine credibility before the email is opened
- Formatting subject lines in a way that visually signals "marketing" rather than genuine correspondence
Keeping your subject lines within a length that displays cleanly across common inboxes is worth checking directly. SeoWolf's Word Counter is a quick way to confirm the length before sending.
Wording gets most of the attention in subject line advice, but formatting is often what a recipient's eye registers first — and first impressions, even at the level of capitalization, genuinely affect whether an email gets opened at all.