The retention marketing glossary.

A/B test

Also called split test

Sending two versions of one email or text to random, equal parts of a segment to learn which one wins on a single metric.

Change one thing at a time, such as the subject line, the offer or the send time, and choose the winning metric before you send. Use placed orders or revenue per recipient for anything with an offer, and clicks for content. Small segments give noisy winners, so test where the audience is big enough to tell.

A sign-up form test, written up

Abandoned cart flow

Also called cart abandonment flow, abandoned checkout flow

An automated series of emails or texts sent when a shopper adds products to their cart, or starts checkout, and leaves without paying.

The first message usually goes within an hour and shows what was left in the cart. A cart flow triggers on add to cart and reaches more people. A checkout flow triggers once the shopper has entered an email at checkout, so it reaches fewer people with more intent.

How to build a cart abandonment flow

Active customer

A customer who has ordered within a set window, chosen to match how often your product is bought.

Twelve months is a common default, but a coffee subscription and a sofa need different windows. Pick one window, use it in every report, and the active count becomes the base for your churn and retention rates.

Average order value (AOV)

Revenue divided by the number of orders over the same period.

AOV = total revenue ÷ number of orders. Bundles, free-shipping thresholds and post-purchase upsells raise it, and broad discounts often lower it. It is one of the three inputs to a simple lifetime value estimate.

Attributed revenue

The revenue an email or SMS platform credits to a message because the buyer opened, clicked or received it within a set window before ordering.

Each platform sets its own default window and model, and both can usually be changed, so attributed revenue from two platforms is not directly comparable. Treat it as a direction, and check it against holdout tests or total repeat revenue in Shopify.

BFCM

Also called Black Friday Cyber Monday

The four days from the Friday after US Thanksgiving to the following Monday, and the busiest sales window of the ecommerce year.

In 2026 it runs from 27 to 30 November. For retention, the work that matters comes after it: many BFCM buyers are first-time customers, and the weeks that follow decide whether they ever order again.

Turning BFCM buyers into repeat customers

Browse abandonment flow

An automated message sent when a known subscriber views a product but does not add it to the cart.

It only reaches people the platform can identify, such as subscribers who arrived from an email or are signed in, so it is smaller than a cart flow. Keep it lighter than a cart reminder: the shopper showed interest, not intent.

How to build a browse abandonment flow

Customer acquisition cost (CAC)

What it costs to win one new customer: marketing and sales spend over a period divided by the new customers won in it.

Comparing CAC with lifetime value shows whether growth pays for itself. When CAC rises, every repeat order a retention programme adds makes the original acquisition cheaper in hindsight.

Churn rate

The share of customers who stop buying in a given period: the opposite of retention.

For subscriptions, churn is explicit because the customer cancels. For one-off purchases it has to be defined: a customer counts as churned once they go a set time without ordering, such as twice your typical gap between orders.

Cohort analysis

Grouping customers by the month of their first order and tracking what share of each group orders again in the months after.

It shows whether retention is improving, which one blended repeat rate hides. If the March cohort reorders faster than the January cohort, something you changed in between is working.

Customer lifetime value (CLV)

Also called LTV

The total revenue, or better the gross margin, a customer is expected to bring in over the whole relationship.

A simple estimate is AOV × purchase frequency × expected lifespan in years, multiplied by gross margin if you want profit rather than revenue. Retention work raises the second and third inputs.

How to calculate CLV on Shopify

Customer retention rate (CRR)

The share of the customers you had at the start of a period who are still customers at the end of it.

CRR = ((E − N) ÷ S) × 100, where S is customers at the start, E is customers at the end and N is new customers won during the period. Taking N out stops acquisition from flattering the number.

How to measure retention, with examples

Deliverability

The share of your emails that land in the inbox rather than in spam or nowhere at all.

It depends on sender authentication, list quality and how recipients engage. Mailing people who never open teaches inbox providers that your mail is unwanted, which is why sunset flows and engaged segments protect revenue.

Double opt-in

A sign-up that is only complete once the subscriber clicks a link in a confirmation email or text.

It slows list growth a little and raises list quality: no typos, no fake addresses and a clear record of consent. Single opt-in adds people straight away and relies on good form design and list hygiene instead.

Email authentication

Also called SPF, DKIM and DMARC

Three DNS records that prove your marketing email really comes from your domain.

SPF lists the servers allowed to send for you, DKIM signs each message, and DMARC tells inbox providers what to do with mail that fails. Since February 2024, Google and Yahoo have required all three from bulk senders, along with one-click unsubscribe and a spam complaint rate below 0.3%.

Email flow

Also called automation

A series of messages that sends itself to each person who meets a trigger, such as joining the list, abandoning a cart or placing an order.

Flows run every day without anyone pressing send. That is why a handful of them (welcome, abandonment, post-purchase and win-back) usually earn more per message than campaigns do.

What automated flows are, and which to build first

Engaged segment

Subscribers who have shown recent signs of life, such as clicking, visiting the site or ordering, within a set window.

Since Apple Mail Privacy Protection arrived with iOS 15 in 2021, Apple Mail records opens automatically, so a segment built on opens alone overstates engagement. Clicks, site activity and orders are firmer signals.

First-party data

Data you collect yourself from what customers do on your own channels: orders, site visits and email clicks.

It is the raw material for segmentation, and unlike third-party cookies it does not depend on browsers or ad platforms. Zero-party data is the part customers tell you on purpose.

Lifecycle marketing

Messaging matched to where each customer is in their relationship with the brand: subscriber, first-time buyer, repeat buyer, VIP or lapsed.

Each stage has one job. Turn subscribers into buyers, first orders into second orders and repeat buyers into loyal ones, and bring lapsed customers back before they are gone.

Loyalty program

A system that rewards repeat purchase with points, tiers, perks or early access.

It works when the reward changes behaviour, such as a second order placed sooner or a bigger basket, rather than discounting orders that would have happened anyway. Most members only notice the program through its emails, so the flows matter as much as the rules.

How to build VIP and loyalty flows

Post-purchase flow

The messages a customer gets after ordering: confirmation and delivery updates, then product tips, a review request and the nudge towards a second order.

It is the main lever on time to second order, because it reaches every new customer while the first purchase is still fresh.

How to build a post-purchase flow

Purchase frequency

How often the average customer orders in a period: total orders divided by unique customers.

A frequency of 1.4 over a year means the typical customer ordered 1.4 times. Of the inputs to lifetime value, it is the one retention work moves most directly.

Repeat purchase rate

The share of customers who have ordered more than once.

Repeat purchase rate = customers with two or more orders ÷ all customers, over the same period. It is the simplest health check for a retention programme, and easy to pull from Shopify customer data.

Replenishment flow

A reminder timed to when a consumable product is likely to run out.

Base the timing on your own reorder data for each product, meaning the days between first and second purchase, not on pack size alone.

How to time a replenishment flow

Retention marketing

Marketing aimed at customers you already have, to get them to buy again, buy more and stay longer.

Email and SMS flows, campaigns, segmentation, loyalty and win-back are its main tools. It is measured on repeat purchase rate, retention rate and lifetime value, not on reach.

What retention marketing covers

RFM segmentation

Grouping customers by recency (how recently they ordered), frequency (how often) and monetary value (how much they spend).

Each customer gets a score on all three, and the combinations become segments. Recent big spenders get early access, lapsed frequent buyers get a win-back, and one-time buyers get a reason for a second order.

Segment

Also called and list

A group of profiles defined by conditions, such as "ordered twice, not in the last 90 days", that updates itself as people meet or stop meeting them.

A list is static: people join it, usually by signing up, and stay until they are removed. Lists record consent; segments decide who gets which message.

SMS consent

The permission a customer gives to receive marketing texts. In the US that means prior express written consent under the Telephone Consumer Protection Act (TCPA).

Several US states add their own rules on texting hours and frequency, and in the UK and EU texting falls under PECR and GDPR. Capture consent at sign-up with clear wording, and store it with a timestamp.

SMS retention marketing, done compliantly

Sunset flow

A last series of messages sent to subscribers who have stopped engaging, before they are suppressed from regular sends.

It asks whether they still want to hear from you, often with a reason to stay. Those who do not respond are taken out of campaigns, which protects deliverability for everyone else on the list.

Suppression

Excluding a profile from receiving messages, without deleting it.

Unsubscribes, hard bounces and spam complaints are suppressed automatically, and unengaged profiles are often suppressed after a sunset flow. Suppressed profiles keep their order history for reporting.

Time to second order

The typical number of days between a customer's first order and their second.

Use the median rather than the average, because a few very slow reorders drag the average out. It tells you when post-purchase and replenishment messages should land, and customers who pass it without reordering are the first to win back.

VIP segment

Your highest-value customers, usually the top slice by spend or order count, treated differently in messaging.

Early access, perks that are not discounts and personal notes tend to work better here than blanket offers, because these customers already buy without them.

Welcome flow

Also called welcome series

The first messages a new subscriber gets after signing up, usually delivering any promised offer and introducing the brand.

It reaches people at their most interested, so the first email goes immediately. Its job is the first order; once that happens, the post-purchase flow takes over.

How to build a welcome flow

Win-back flow

Messages sent to customers who have gone longer than usual without ordering, to bring them back before they are lost.

Time it from your own repeat data, around the point where most customers who reorder already have, and escalate gently: a reminder first, an offer later.

How to build a win-back flow

Zero-party data

Information a customer chooses to tell you, such as quiz answers, preferences or a birthday.

Because it is volunteered, it is accurate and comes with consent. Use it straight away: a skin-type answer should change the very next email.