In one embodiment, one or more computing devices receive, from one or more mobile devices respectively associated with one or more users, one or more sets of data, wherein each set of data comprises: a user identifier indicating to which user the set of data corresponds; a location where the corresponding user was at; and a time when the corresponding user was at the location. The computing devices store the one or more sets of data; and extract one or more statistics from the one or more sets of data that represent behavioral pattern of at least one of the one or more users.