Segment

A group within an audience that shares a need or a habit. You cannot speak to everyone at once, so you choose who first.

Segmentation admits that the market is plural: different people arrive with different jobs for the same product, and a message tuned to one job puzzles the others. A segment worth the name shares a situation, a need, a habit, not merely a statistic.

Choosing who first is strategy in miniature. The tempting segment is the largest; the correct one is where the fit is sharpest and the story will be retold. Win a narrow room completely and adjacent rooms hear about it. Address the whole floor at once and no room considers itself spoken to.