User acquisition (UA) covers buying installs or in-app actions on channels such as Google App Campaigns, Meta, Apple Search Ads, TikTok, and the large mobile ad networks. The core economics are simple to state: acquire users for less than they will be worth, fast enough that cash can be recycled.
In practice, UA is a signal problem. Costs are visible immediately; value arrives over months. Most UA mistakes come from scaling on immature evidence, trusting blended averages, or optimising to an event that is a poor proxy for value.