What is user acquisition (UA)?

What a UA function does

At its simplest, UA buys users for less than they are worth. That reduces to three continuous jobs: finding channels that work, producing creative that performs, and measuring accurately enough to tell the difference between the two.

The constraint that shapes everything is that acquisition cost rises with volume. The cheapest audiences are exhausted first, so a channel that looks excellent at small scale frequently stops working at the scale the business needs — which is why UA is a search problem rather than an optimisation problem.

The economics

LTV against CAC sets the ceiling, and payback period sets the pace. A business can have a healthy ratio and still be unable to grow, because the cash is committed today and returned over two years.

The most common structural mistake is planning against the LTV of early cohorts. Early adopters are systematically more valuable than the users a scaled campaign brings, and acquisition budgets set against their value become unprofitable at exactly the moment they are supposed to be working.

How the discipline changed

• Identifier loss removed granular targeting and much of the measurement — see ATT.
• Campaign structures consolidated, because privacy thresholds punish fragmentation.
• Creative became the main lever, since it is one of the few inputs still fully under a team's control — see IPM.
• Causal measurement returned, because attributed numbers stopped being trustworthy enough to allocate on.

AI surfaces as an acquisition channel

AI assistants are a genuinely new acquisition surface with an unusual profile: low volume, high intent, and measurement that conventional UA instruments read badly.

The mistake to avoid is applying a standard CPI or last-click ROAS threshold to it. Users arriving from a recommendation have often already compared options, and a substantial share of the influence produces no click at all — so the channel will underperform on attributed metrics and outperform on cohort quality. Cohort it separately and measure it with a holdout.