SMS Marketing Strategy
SMS is a different channel with different economics, not 'email but shorter'
SMS marketing gets treated by many teams as a smaller, text-only version of email, but its underlying economics and recipient tolerance are fundamentally different. Open rates for SMS routinely exceed 95-98%, nearly all within minutes of send, because text messages interrupt in a way email doesn't — they land on a lock screen, not in a queue the recipient checks on their own schedule. That same interruption power is exactly why SMS fatigue accumulates faster and more visibly than email fatigue: a recipient who's irritated by over-mailing unsubscribes from email quietly; a recipient irritated by over-texting often reports the number as spam, which carries carrier-level consequences, not just list-level ones.
Opt-in requirements: stricter and more explicit than email
SMS marketing consent requirements are materially stricter than email's, governed in the US primarily by the TCPA (Telephone Consumer Protection Act) and enforced through carrier-level filtering as well as legal liability. Express written consent is required specifically for marketing texts — a general 'sign up for updates' checkbox that also covers email does not automatically cover SMS consent; the opt-in language must specifically disclose that message/data rates may apply, that consent isn't a condition of purchase, and must capture the phone number through an action clearly tied to agreeing to receive texts (a double opt-in via a confirmation text is considered best practice and is often required by SMS platform providers themselves, like Attentive or Klaviyo SMS).
Compliance isn't just legal risk — carriers themselves (via 10DLC registration requirements in the US) throttle or block unregistered or poorly-behaved sending numbers, meaning a non-compliant SMS program can simply stop delivering with no warning, independent of any lawsuit risk.
[Checkout opt-in checkbox - compliant pattern]
[ ] Text me exclusive offers and order updates.
By checking this box, you agree to receive recurring
automated marketing texts from Brand at the number provided.
Consent is not a condition of purchase. Msg & data rates
may apply. Reply STOP to unsubscribe, HELP for help.
[Confirmation text sent immediately after opt-in - double opt-in]
"Brand: You're confirmed for texts! Reply STOP anytime to
unsubscribe. Msg & data rates may apply. 4msgs/mo avg."
[STOP handling - must be automatic, immediate, carrier-enforced]
Reply STOP -> instant suppression, confirmation text sent,
no further marketing texts to that numberSMS vs. email — channel fit and fatigue economics
| Dimension | SMS | |
|---|---|---|
| Open rate | 95-98%, within minutes | 15-30% typical, hours to days |
| Consent standard | Express written consent, double opt-in common | Implied or explicit opt-in, less stringent |
| Fatigue threshold | Low — 2-4 sends/month is a common ceiling | Higher — daily sends tolerated by some segments |
| Opt-out consequence of overuse | Carrier spam report, number blocking | Quiet unsubscribe, list attrition |
| Best use case | Time-sensitive, high-urgency (flash sale, shipping alert) | Nuanced content, storytelling, longer-form offers |
| Cost per message | Materially higher than email per send | Near-zero marginal cost per send |
SMS fatigue compounds faster because the channel is more personal
Where SMS beats email — and where it doesn't
SMS's structural advantage is near-immediate attention for time-sensitive messages: a cart abandonment text sent 1 hour after exit, a flash sale with a same-day deadline, or a shipping delay notification all benefit from the interruption SMS provides that email's queued nature doesn't. These use cases justify SMS's higher cost-per-send because the urgency genuinely matches the channel's strength.
SMS is a poor fit for nuanced, exploratory, or long-form communication — a 160-character limit (before messages split into costlier multi-part segments) can't carry the same storytelling, product education, or multi-offer complexity email handles natively. Programs that try to replicate full email campaigns via SMS typically see fatigue and opt-out spikes faster than the channel can sustain.
Segment SMS by urgency fit, not just by the segments used for email
What's next
SMS isn't the only interruption-based channel competing for attention alongside email — push notifications follow a related but distinct set of permission and fatigue rules worth understanding on their own terms.
Next: Push Notification Strategy →
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