In the software industry, people who interact with software products are called users. Users are not always customers, but occasionally can be members of the client.

In The Inmates are Running the Asylum, Alan Cooper warns against the elastic user, which is a phenomenon in which an imaginary user changes role and direction to suit an argument around certain particular features. The net effect is an inconsistent product with poor conceptual integrity. Cooper's prescription to avoid this is the introduction of personae, which serve as sufficiently rigid archetypes for establishing interactions.