Cohorts are a privacy-preserving way of grouping users according to which asymmetric queries they appear in.

The maximum size of cohorts, for example 100, means a publisher cannot learn anything significant about the count or result size of advertiser queries. Cohort size is set by the system and cannot be changed by a user.

When different advertisers run asymmetric queries against the same activation dataset, cohorts group people who have appeared commonly across these different queries according to their presence or absence in the various queries.