1. A method comprising: receiving, by a data-processing system, a plurality of data points D that correspond to a first user, wherein each data point in the plurality of data points D represents a visit by the first user, the visit occurring at one or both of i) a determinable geolocation and ii) a determinable time, and wherein the plurality of data points comprises at least a first data point that occurs at a first time t 1 , d(t 1 ); determining, by the data-processing system, an entropy of the plurality of data points D, based on a number of predetermined places to which the data points in the plurality of data points D correspond; and estimating, by the data-processing system, a description of the first user, wherein the description is based on the determined entropy.