Personalisation has been a stated priority in every business I have worked in for the last decade. In most of them, what was actually running was a first name in a subject line and a recommendation widget nobody had evaluated.
That is not a criticism of the teams. Real personalisation requires a unified, trustworthy, consented view of behaviour, and a channel wired to act on it. Without both, what is left is decoration.
The three levels
- Cosmetic. Name, location, last purchase referenced. Cheap, mildly effective, occasionally embarrassing when the data is stale.
- Segmented. Genuinely different content for genuinely different groups. This is where most of the value sits and where most businesses stop short.
- Individual. Decided per person, in the moment, by a model. Powerful, and only possible on top of the second level being solid.
Almost everyone wants to jump from the first to the third, because the third is what gets discussed at conferences. The second is where the money is and it is unglamorous, because it looks like maintaining segments and writing more variants.
Everyone wants to jump straight to individual personalisation. Almost all the value is in the level they skipped.
When personalisation actively hurts
Recommending what someone just bought. Continuing to sell to an existing subscriber. Cheerful marketing arriving the day after a complaint. Each of those tells the customer that the business does not know them, which is worse than not personalising at all, because effort was clearly expended.
Suppression rules matter more than recommendation logic and get a fraction of the attention.
What I would build first
Not a model. A set of suppressions and a handful of well chosen segments, running reliably across every channel. That is unglamorous, quick, and it improves the customer experience immediately.
Then, with a foundation and a channel that can act, the model becomes worth building, and there is something for it to do.
The one measure worth watching
Not open rate or click rate, both of which improve when a message is merely more relevant. Watch retention and repeat purchase among the personalised group against a holdout. It is a slower measure and it is the one that tells you whether any of this worked.