All articles
Every guide and tool page, grouped by topic, newest first within each.
The basics
What retention marketing covers, and where the numbers most often used to justify it come from.
1 articleThe numbers
Most of these metrics have more than one published formula, and the answer can move a lot between them. Each guide sets the versions side by side.
6 articlesWhat is average order value?
Twelve of fifteen publishers divide revenue by orders. They do not mean the same thing by revenue — three strip taxes and shipping, one keeps them, and a store platform's own column is a third thing again. What AOV counts, and why yours may not compare.
What is purchase frequency?
Nine publishers give the same ratio: total orders divided by unique customers. Two of them then print a repeat-buyer benchmark further down the same page without saying it is a different quantity. What the number counts, and why yours may not compare.
What is repeat purchase rate?
Repeat purchase rate is the share of customers who bought more than once. The published formulas disagree about which customers go in the denominator, about whether the window is a month or a lifetime, and about whether one of the metric's own names points at a completely different number. What each version measures, and what to write down beside it.
What is customer churn rate?
Churn rate is the share of customers a store loses over a period. The published formulas disagree about who is in the denominator, about what counts as leaving, and about whether the number is monthly or annual. What each version measures, and what to write down beside it.
What is customer lifetime value?
Your platform shows what a customer has already spent, plus a forecast of the next year. The published formulas run on a lifespan of several years, and some multiply by profit margin. What each version answers, and where they disagree.
How is customer retention rate calculated?
Klaviyo's own example gives 64%, dividing repeat buyers by one-time buyers. Divide the same repeat buyers by all 92,000 customers and it is 39%. Seven formulas answer the question.
Email flows
The automated emails a store sends, what starts each one, and where the published guides disagree about how to set it up.
6 articlesWhat is a replenishment email?
A replenishment email reminds a customer to reorder a product shortly before it runs out. Setting one up is easy. The hard parts are picking the delay and telling whether the email adds reorders or just takes credit for ones already on the way.
What is a browse abandonment email?
One platform sends it when a shopper views a product. Another sends it only to people who never reached a product, and sells the first version under a different name. The delays run from one hour to twenty-four.
What is a win-back email?
A win-back email is an automated message or sequence sent to people who previously bought or engaged and then went quiet. The hard part is not the phrase. It is the inactive threshold: published defaults run from 45 days to 360 days, while several guides say the right clock depends on the buying cycle.
What is a post-purchase email flow?
A post-purchase email flow is the automated sequence a store sends after someone buys. The published guides disagree about which emails are in it, how many it holds, and whether the clock starts at the order or at delivery — and three of them disagree with themselves. What each version means, and what to write down beside your own number.
What is a welcome email flow?
A welcome email flow is the automated sequence a store sends after someone joins its list. The published guides disagree about how many emails it holds, how fast the first one goes out, whether a first purchase belongs in it, and what the open rates everyone quotes are counting. What each version means, and what to write down beside your own number.
What is an abandoned cart email?
One platform sends it when a shopper adds to their cart. Another sends it only after checkout starts. A third starts a ten-minute clock once an email address is typed. The 70% figure everyone quotes counts a fourth group again.
Segments and targeting
Splitting one list into groups that each get a different email, and the scoring methods used to decide who goes where.
2 articlesWhat is email list segmentation?
Email list segmentation splits one list into groups that each get a different email. Building segments is easy. Knowing which ones change what people do is harder, and field experiments show the obvious picks are not always the ones that respond.
What is RFM segmentation?
RFM segmentation scores every customer on recency, frequency and monetary value. The three labels are settled. The scale is not: published models run 1-3, 1-4, 1-5 and 1-10, the direction flips between vendors, and the same code 111 names the best customer in one system and the worst in another.
AI in retention
How churn prediction, predicted lifetime value and next-best-action work, and how to read what each model gives back.
5 articlesNext best action vs next best offer: what is the difference?
Next best offer picks a sales offer or promotion to show. Next best action can also choose a message, service support, or no contact.
What is next-best-action in retention marketing?
Next-best-action chooses what to do for one customer now—not just who is likely to respond. See the action set, rules, ranking, and holdout a retention policy needs.
What is predictive churn, and how do the models work?
Predicted churn is a per-customer estimate of churn risk, and three different quantities travel under the name. How buy-till-you-die models and churn classifiers work, why the definition of churn is something you choose, and what to check before you act on a score.
How is predicted customer lifetime value calculated?
Two ways to calculate predicted CLV: models that read only each customer's order history, and machine learning trained on past customers. How each one works, why customers with no repeat purchase are the hard part, and how to check the number.
What does AI actually do in email marketing?
AI gets applied at six points in an email programme, and the vendor documentation is precise about the mechanical ones and silent about the decisions. What the help pages promise, what they refuse, and where the automation stops.
Choosing a tool
Email platforms compared by the reason you are looking, with prices and plan limits dated to the day they were read.
2 articlesBest email marketing platform for Shopify in 2026: five choices by fit
Compare Shopify Messaging, Seguno, Omnisend, Klaviyo and Mailchimp by Shopify data, automation, channels and billing model—then choose for the work your store needs.
Klaviyo alternatives in 2026: compare replacements by why you're switching
Five email platforms that can replace Klaviyo for an online store, compared by why the current setup stopped fitting, capability tradeoffs and plan pricing.
Other guides
4 articlesWhat is AI customer retention?
AI can predict which customers may leave, choose an intervention, or help deliver it. The retention question is whether that decision makes more customers return or renew.
Do AI agents improve customer retention?
Trials show that AI agents can change engagement and service speed. Neither result alone proves customers stay longer. Here is what the evidence supports and how to test retention lift.
Does AI-written email copy improve retention?
Research finds useful short-term results for AI-written email copy, but not a general retention lift. Here is how to test the copy method against repeat purchasing.
How is AI customer segmentation different from RFM segmentation?
RFM groups customers by purchase recency, frequency, and spend. AI segmentation may group by similarity across chosen data or target a predicted outcome. Here's how to compare them.