[eesmith]

Persona development in user-centered design (see https://en.wikipedia.org/wiki/Persona_(user_experience) ) puts a face on the imaginary group by developing a single persona to represent that group.

Of course, there are many possible users, so there may be many personas. Persona development lets you decide which one or two to prioritize.

Cooper use the term "The Elastic User" to describe what this essay describes as "The Faceless Other", and the associated vagueness.

If you are writing software for software developers then you can likely follow the HP approach - "design for the guy at the next bench".

If you write software for non-software developers, it's harder to know if your personal views are a good guide.