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As a contact list grows, the reflex is to write to everyone: the new offer, the webinar invitation, the article of the month. Each send reaches a few interested people and many others who are not. Those unsubscribe, ignore, or report the message as spam. After a few months, the useful messages land in spam too, and the list is worth less than before.
Segmentation means doing the opposite: sending each message only to the people it concerns. This guide is for teams of 20 to 500 people who email their prospects and customers. It extends our guide to marketing automation for SMEs.
In short
A message sent to someone it does not concern has a cost: an unsubscribe, a spam report, and worse delivery for the next sends.
Four criteria are enough to split a list: what the person asked for, their profile, their behaviour, their stage in the relationship.
Opens are no longer a reliable signal; clicks, replies, enquiries and purchases are.
Three to five well-kept segments beat thirty nobody maintains.
A segment only makes sense if it receives a message written for it.
What a send to the whole list costs
Each time a recipient reports a message as spam, their mailbox provider takes it into account for the next sends from the same address. The big providers publish their thresholds. Google’s, for instance, apply to every sender, with stricter requirements for the largest volumes.
of messages reported as spam: the rate Google advises staying below
the rate never to reach
messages a day to Gmail: the threshold above which stricter rules apply, including one-click unsubscribe
These rates are low: a handful of reports on a send to a few thousand addresses is enough to exceed them. The same document asks senders to avoid writing to people who did not sign up to receive their messages. Sending less, but to the people expecting the message, is first of all a way to stay readable.
Four ways to split a list
- What the person asked for. A newsletter sign-up, a guide download, a webinar registration: each one signals an interest and a consent. In France, the data protection authority accepts emailing a professional without prior consent if the subject is related to their profession, they were informed and can easily refuse; an individual consumer must have consented first. What the person asked for is also what they are most likely to read.
- Profile. Sector, company size, role, country and language. A finance director and a technical lead do not expect the same message about the same product, and a German reader does not expect an email in English: language is chosen with the market, as our guide to international SEO explains.
- Behaviour. What the person did: clicked on a topic, attended a webinar, downloaded content offered for their address, asked for a quote, bought.
- Stage in the relationship. Prospect, new customer, loyal customer, former customer. A new customer expects help getting started, not the welcome offer sent to prospects.
Definition
RFM segmentation
A common method in ecommerce: each customer is ranked by the recency of their last purchase, the frequency of their purchases and the monetary amount spent. It splits customers into a few groups (loyal ones, those drifting away, those who bought only once), and each group gets a different message.
Opens are no longer a reliable signal
Many segmentations still rely on “opened” or “did not open”. That signal has blurred. On Apple devices, Mail’s activity protection downloads remote content in the background by default, regardless of whether you engage with the email. A message never read can therefore show up as opened.
Watch out
Do not segment on opens
A “regular openers” segment today mixes real readers with mail apps that load images on their own. Signals that require a deliberate action remain reliable: a click, a reply, an enquiry, a purchase, an event registration.
How many segments?
Fewer than you think. Each segment needs its own message, its own rhythm and someone to keep it up. A mid-sized team starts well with three to five segments, for example: prospects in a priority sector, new customers, loyal customers, contacts inactive for a year. Segments are refined later, when the numbers justify it.
From list to message
- Clean data
Duplicates merged, fields filled in the same way, the source of each contact.
- A few segments
Defined by a written rule that the CRM applies on its own.
- One message per segment
Written for that group, based on what it asked for or did.
- Measurement
Replies, enquiries and sales per segment, not just per send.
The first step is often the longest: segmentation on dirty data sends the right message to the wrong people. The method is in our guide to cleaning CRM data.
From the field
A consenting list, never contacted
On an online plush toy store we are putting back on its feet, the initial review counted 972 customer addresses that had agreed to receive emails and had never been contacted, and 3.2% repeat customers. The work that followed: segmentation by recency, frequency and amount, which is then used to choose who receives which message, rather than one identical send to the whole list.
What segmentation changes for sales
Sending less does not mean selling less. A message written for a precise group talks about its problem, in its words, and invites a reply. The people who reply, click on an offer or ask for a conversation are the ones sales should call back: the rule that passes them on is described in our article on the marketing-to-sales handoff. Salespeople, for their part, know better than anyone which profiles sign: their feedback is used to redefine the segments.
Segmentation applies to content too. A customer case study in the reader’s sector convinces more than a case taken from elsewhere; a newsletter issue can have a common part and a box specific to each segment. AI helps adapt a message per segment, provided each version is reviewed and sourced; the split between tool and writer is detailed in AI and digital marketing: what changes for agencies.
Measuring per segment
The right indicator is not the open rate of a send, but what each segment produces over a quarter: replies, enquiries, sales, unsubscribes and spam reports. A segment that never replies is paused, or receives one last message asking whether it wants to continue. Our guide to automated marketing reporting shows how to pull these numbers every week, and our article on marketing attribution how to connect a send to a sale.
Where to start
Export the list and look at three columns: the source of each contact, the last deliberate action (click, reply, enquiry, purchase) and the stage in the relationship. Define three segments from these columns, and write one message for each. Take contacts with no action for a long time out of regular sends. Before pressing “Send”, our method for running an email campaign lists the useful checks, and the year’s marketing plan says which segments to prioritise. The same segments also help choose what to publish from the leader’s LinkedIn profile.
For segmentation kept up by the CRM and sends that follow each contact through to the sale, our digital marketing offer starts from your existing data.
Frequently asked questions
What is segmentation in marketing?
It is splitting a contact list into groups that share an interest, a profile, a behaviour or a stage in the relationship, so that each group receives a message that concerns it. In email, it avoids writing the same thing to everyone, which drives up unsubscribes and spam reports and weakens delivery for every later send.
How many segments should you create?
Three to five to start, each with a written rule and its own message. A segment that does not receive a different message serves no purpose. Refine later, when the numbers show that a group reacts differently from the others, and when the team has the time to write for it.
Should you delete inactive contacts?
Not necessarily delete them, but take them out of regular sends. A contact with no click, reply or purchase for a long time can receive one last message asking whether they want to continue. Without a reply, they leave the sending list. This lowers the risk of spam reports and keeps statistics that reflect real readers.
What tools do you need to segment a contact list?
The CRM or email tool you already use is often enough, provided it keeps the source of each contact and their actions. What matters is that segments are calculated automatically from a written rule, not by hand before each send. The choice of tool comes after the quality of the data.
Sources
- CNIL, la prospection commerciale par courrier électronique (new tab)cnil.fr
- Apple, Mail Privacy Protection & Privacy (new tab)apple.com
Jim · founder of Brain Plus AI
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