Email Marketing

Email deliverability, list management, sequences, segmentation, and campaign optimization.

Security Scan

This is an instruction-only email-marketing guide that is internally consistent with its stated purpose and requests no credentials, installs, or system access.

Purpose & Capability

The name and description (email deliverability, list management, sequences, segmentation, campaign optimization) match the SKILL.md content. All guidance relates to email marketing practices; nothing requested or instructed is unrelated to the described purpose.

Instruction Scope

SKILL.md contains operational marketing guidance only (deliverability, segmentation, sequences, testing, compliance). It does not instruct the agent to read local files, access environment variables, call external endpoints, or collect/transmit user/system secrets.

Install Mechanism

There is no install specification and no code files. Nothing will be written to disk or executed by the platform as part of this skill — lowest-risk configuration for an instruction-only skill.

Credentials

The skill declares no required environment variables, credentials, or config paths. That is proportionate for an advice/reference skill about email marketing. (If you later connect this guidance to an ESP, that integration would require API keys, but those are not requested here.)

Persistence & Privilege

always is false and model-invocation is allowed (the platform default). This is not risky by itself for an instruction-only skill, but note the skill's source is 'unknown' and there is no homepage—you may want to prefer skills from identifiable authors if you require provenance or accountability.

Assessment

This skill is an advisory guide only: it asks for no credentials, has no install steps, and does not access your system. It's internally coherent and low-risk to install. Before you rely on it in production: 1) confirm the guidance matches your email service provider's requirements (you will need proper ESP API keys when you integrate); 2) follow legal/regulatory advice for your jurisdictions (GDPR, CAN-SPAM); 3) don't paste sensitive customer data into the agent when asking for help; and 4) consider preferring skills with an identifiable source or homepage if provenance and maintainability matter to you.

Deliverability Foundations

• Authenticate all sending domains: SPF, DKIM, and DMARC — missing any one tanks deliverability
• Warm up new domains/IPs: start with 50-100 emails/day, increase 20% daily over 2-4 weeks
• Never buy email lists — purchased lists destroy sender reputation permanently
• Clean list regularly: remove bounces immediately, unengaged after 90 days
• Monitor blacklists: MXToolbox, Google Postmaster Tools — problems compound if not caught early

List Health Metrics

Metric	Healthy	Warning	Critical
Open rate	>20%	10-20%	<10%
Click rate	>2%	1-2%	<1%
Bounce rate	<2%	2-5%	>5%
Unsubscribe	<0.5%	0.5-1%	>1%
Spam complaints	<0.1%	0.1-0.3%	>0.3%

• One spam complaint per 1000 emails is the danger zone — above this, inbox placement drops sharply

Subject Lines

• 40-50 characters optimal — truncates on mobile after 35-40
• Personalization works: name or company in subject increases opens 10-20%
• Curiosity beats clarity for opens, but clarity wins for clicks — balance based on goal
• Avoid spam triggers: ALL CAPS, excessive punctuation!!!, "free", "act now"
• Test emoji: works for some audiences, hurts others — A/B test before committing
• Preview text is second subject line — don't waste it with "View in browser"

Email Sequences

Welcome sequence (5-7 emails over 2 weeks):

1. Immediate: Deliver promised value + set expectations
2. Day 1: Best content or quick win
3. Day 3: Story/origin + values
4. Day 5: Social proof + case study
5. Day 7: Soft offer or deeper engagement
6. Day 10: Address common objection
7. Day 14: Clear CTA

• First email in sequence has highest open rate — make it count
• Space emails 1-3 days apart — daily is too aggressive for most audiences

Segmentation

• Segment by behavior, not just demographics — what they clicked matters more than job title
• Minimum viable segments: new subscribers, engaged (opened in 30 days), unengaged, customers
• Tag on every click — builds behavioral profile automatically
• Sunset unengaged subscribers after 90 days — send re-engagement, then remove
• VIP segment for highest engagement — reward them with early access, exclusives

Timing and Frequency

• Tuesday-Thursday mid-morning performs best on average — but test your audience
• B2B: business hours. B2C: evenings and weekends can work
• Frequency depends on value: daily works if valuable, weekly fails if boring
• Let subscribers choose frequency — reduces unsubscribes significantly
• Send time optimization: most ESPs offer this, use it

Campaign Types

• Newsletter: regular value, builds relationship, low direct conversion
• Promotional: clear offer, urgency, direct conversion focus
• Transactional: receipts, confirmations — highest open rates, add value here
• Re-engagement: "We miss you" + incentive + easy unsubscribe
• Announcement: product launches, major updates — segment to interested only

Writing for Email

• One goal per email — multiple CTAs dilute response
• Write for skimmers: bold key phrases, short paragraphs, bullet points
• P.S. lines get read — put secondary CTA or key point there
• Plain text often outperforms HTML for personal-style emails
• Mobile-first: 60%+ open on mobile — single column, large tap targets

Automation Triggers

• Sign up → Welcome sequence
• Purchase → Onboarding + cross-sell sequence
• Abandoned cart → 3-email recovery (1h, 24h, 72h)
• No open in 30 days → Re-engagement sequence
• Link click → Tag and trigger relevant follow-up
• Date-based → Birthday, renewal reminder, anniversary

A/B Testing

• Test one variable at a time: subject, send time, CTA, from name
• Need 1000+ recipients per variant for statistical significance
• Subject line tests: 20% of list first, winner to remaining 80%
• Measure what matters: opens for subject, clicks for content, conversions for offers
• Document every test — institutional learning prevents repeat experiments

Common Mistakes

• Sending to entire list always — segment or face declining engagement
• No double opt-in — leads to fake emails and spam traps
• Ignoring mobile preview — broken layouts kill credibility
• Same email to all segments — personalization is expected now
• Hard selling too early — value first, offer later
• Ignoring unsubscribe feedback — they tell you what's wrong

Compliance

• Include physical address in every email — required by CAN-SPAM, GDPR
• Unsubscribe must work within 10 days — one-click preferred
• Honor opt-outs immediately — delayed removal is illegal in many jurisdictions
• GDPR: explicit consent required, document it, allow data deletion
• Separate consent for different email types — marketing vs transactional