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GrowthVector.io

Copywriting

26%
Open lift from personalization
202%
Better CTR with personalized CTA
7 words
Avg high-performing subject line
40 chars
Mobile subject line cutoff

Subject Lines & Open Rates

Subject Lines: The Attention War

Email open rates are compromised by Apple Mail Privacy Protection, but subject lines still determine whether an email gets opened.

Critical Shift: MPP & Open Rates

Since iOS 15, Apple Mail Privacy Protection pre-fetches and auto-opens a large share of emails delivered to Apple Mail users, inflating reported open rates. A/B testing subject lines using Open Rate is now statistically invalid.New Standard: Test subject lines by Click-Through Rate (CTR) or Reply Rate.

TechniqueImpactExample
Numbers/Specificity+2.5% opens, +7.4% replies"3 ways to improve your email"
QuestionsHigher curiosity trigger"Is your email list costing you money?"
Action verbsSignals agency and benefit"Unlock your first sale today"
Urgency (genuine)Time-bounded motivation"Last 24 hours: 30% off ends tonight"
Curiosity gapsIncomplete prompts wanting to know more"The #1 mistake we all make with email..."
First-name personalization+26% opens"John, your exclusive offer inside"

Format & Conversion

Preview Text: The Underused Opportunity

35-140 characters appearing below the subject line. Most marketers leave this real estate empty or rely on whatever the email client auto-extracts from the body.

ClientCharacters VisibleNotes
Mobile35-50First line is read by 99% of recipients
Desktop100-140Second line read by ~25%
Auto-pullN/AGmail/Outlook extract body if not set explicitly

The Auto-Pull Problem

When preview text is not explicitly set, email clients auto-extract body text, often rendering "View Online | Click here | Hi [Name]," which adds no value and looks amateur.

Strategic Use
  • Never repeat the subject line
  • Complement the subject and answer "What is in this for me?"
  • Write first 50 chars for mobile, then optimize remaining for desktop
Example

Subject: "Your 10% Off Ends Soon!"

Preview: "Complete your purchase within 2 hours for the discount"

Plain Text vs HTML: The Performance Paradox

The results are counterintuitive to most marketers' assumptions. Plain text often wins.

MetricPlain TextHTMLSource
Conversions from existing customersHigher shareLower sharePer Litmus A/B tests (magnitude varies)
Open rate with GIF vs plainBaselineOften lowerHubSpot A/B tests (GIF ~37% lower)
Open rate with image vs plainBaselineOften lowerHubSpot A/B tests (image ~25% lower)
DeliverabilityHigherLower (more spam filter scrutiny)Multiple

Call-to-Action Optimization

CTAs are email marketing's conversion lever. A single prominent CTA typically outperforms multiple competing CTAs by reducing choice paralysis.

CTA Placement (typical distribution observed across email campaigns):
PositionUsagePerformance
Top third (above fold)38%Highest CTR with sufficient context
Bottom third35%Works on short emails, fails on long
Middle27%Least common but can work with proper flow

Do

  • One primary CTA (80% of emails)
  • Above the fold for promotional
  • After sufficient value build-up
  • 44x44px minimum for mobile tap

Do Not

  • Use "Click Here" (generic)
  • Crowd multiple CTAs together
  • Ask readers to act before context
  • Use sharp corners (dated look)

Design Tips

  • Rounded corners (more clickable)
  • Sufficient white space around
  • Contrasting color
  • Personalized copy (+202% CTR)

Storytelling & Emotional Architecture

Storytelling and Emotional Architecture

Stories trigger emotional response, which drives memory formation and action better than feature lists. Research shows stories activate similar brain regions as physical experiences (Speer et al., 2009).

Reading "I was stuck, I tried X, I succeeded" triggers more brain activation than "Our product solves X problem." Stories create transportation. Readers temporarily live the narrative.

The 6-Email Storytelling Sequence Framework:
1

Origin/Connection Story

Share your personal origin story or company mission

Build rapport and trust
2

Impact Story

Before/after of a customer win

Reassure they are not alone
3

Aspirational Story

Customer journey from start to success

Help visualize potential future
4

First-Step Story

The very first action a successful customer took

Overcome paralysis
5

Overcoming-Doubt Story

Customer who almost did not take action but pushed through

Address objections
6

Call-to-Action Story

Consequences of action vs. inaction

Create urgency

Copywriting Quick Reference

Subject Line

  • 7 words average
  • 40 chars mobile
  • Front-load key info
  • Numbers +2.5% opens

Preview Text

  • 35-50 chars mobile
  • 100-140 desktop
  • Never repeat subject
  • Answer "What is in it for me?"

CTA

  • One primary CTA
  • 44x44px minimum
  • Personalized copy +202%
  • Rounded corners

Format

  • Plain text for cold outreach
  • HTML for visual products
  • Always include plain fallback
  • Test both formats