Segments are categories of inferences or information about users’ interests or characteristics that are created, acquired, bought, sold, or used by us and third-party data providers integrated with the AppNexus Platform.
When unique identifiers (e.g., cookies or mobile advertising identifiers) are placed into segments, this creates what is known as "segment data".
These unique identifiers allow us/third-party to use their inferences about a device or a user to create or enhance a profile about that device or user.
A user can be a member of any number of segments depending on inferences about that user's personal preferences (determined by the user's online usage and the clients' proprietary offline data that they can match to our cookies or mobile advertising identifiers).