1. A non-transitory computer-readable medium embodying a program executable in a computing device, the program comprising: code that identifies a plurality of users for which at least one segment assignment in at least one segment of interest is known based upon a respective user account of individual ones of the plurality of users; code that identifies at least one of a plurality of historical user-behaviors that is logged by the computing device and that is associated with at least a subset of the users; code that calculates for the at least one of the plurality of historical user behaviors, a percentage of the users in each possible segment assignment associated with the at least one segment of interest that exhibit the at least one of the plurality of historical user-behaviors; code that stores the percentage in a data store; code that identifies a subsequent user by observing a behavior associated with the subsequent user, the behavior corresponding to an interaction between the subsequent user and the computing device; code that identifies one of the plurality of historical user behaviors corresponding to the behavior; code that identifies a first segment of interest associated with the one of the plurality of historical user behaviors; code that associates the subsequent user with a first segment assignment in the first segment of interest associated with the highest percentage of users for which the first segment assignment is known who have exhibited the behavior; and code that calculates a confidence score associated with the first segment assignment of the subsequent user.