1. A computer implemented method of selecting consumers to receive content on a computer network, comprising: obtaining, at a data processing system, a user list, the user list indicating a first plurality of users each associated with at least one of a group of features corresponding to internet activity of the first plurality of users, wherein the group of features includes information about at least one of URL visits, internet browsing activity, link activity, and conversion information of each of the first plurality of users; selecting a subgroup of features from the group of features; identifying a plurality of clusters of users of the first plurality of users based on the group of features corresponding to internet activity of the first plurality of users; identifying a first cluster of users of the first plurality of users, each user of the first cluster of users being associated with at least one particular feature of the subgroup of features; identifying, from a second plurality of users, a first supplemental user associated with at least a supplemental feature, the supplemental feature including information about at least one of URL visits, internet browsing activity, link activity, and conversion information of the first supplemental user; determining a correlation between the supplemental feature and one of the at least one particular feature of the subgroup of features; generating an expanded user list, the expanded user list comprising at least one user of the first cluster of users and the expanded user list including the first supplemental user; adding the first supplemental user to the first cluster of users; and adding the first supplemental user to a second cluster of the plurality of clusters.