An audience selection system for the selection of an entity, based on an entity's consumption history without requiring the storage of a content descriptor for identifying content previously accessed by the entity. By directly and/or indirectly observing the usage of words used to locate content through a search engine over time for a population, a list of depersonalized keywords can be discovered, creating the ability to characterize content based on depersonalized keywords. A protected consumption history can be recorded for an entity using depersonalized keywords instead of recording a content descriptor for identifying the content. Depersonalized keywords do not uniquely identify content. Associating depersonalized keywords with an entity does not mean that the entity has used those depersonalized keywords; it only means that the entity has accessed content which has been accessed in the past by other entities in a population using the depersonalized keywords.