Defining the audience for a campaign · Ceded (since 2013)

On 20 March 2013, Facebook opened lookalike audiences to advertisers, building a target population automatically from a seed list of existing customers instead of from a planner's written definition of a segment.

Segmentation used to be an argument on paper. A planner defined a group by age, income, region and habit, defended the definition in front of the client, and bought against it. The seed list removed the definition, since the advertiser now supplies a few thousand customers and the platform infers the resemblance without ever having to state what it consists of. What people keep is the choice of which customers seed the list, the exclusions the law imposes on housing, credit and employment advertising, and the judgment that a group should not be targeted at all. The loss is legibility, because a segment nobody can describe is also a segment nobody can audit.