1. A method, comprising: receiving, for at least one website, a first plurality of data points related to each visitor of a first plurality of visitors to the website, the first plurality of data points comprising at least an identification of the visitor and an interaction of the visitor with the website; receiving, at a computing device, a target audience comprising at least some of the first plurality of visitors having a known, desired interaction; receiving, responsive to a user input to the computing device, a plurality of selection rules defining tolerances for a similarity audience, the plurality of selection rules including a correlation score and an audience composition index; selecting, using the computing device, the similarity audience from a plurality of clusters defined by a number of unique visitors, at least some of the unique visitors sharing at least one interaction in common, and the similarity audience comprising at least one cluster of the plurality of clusters satisfying the plurality of selection rules; and generating, from the computing device and for electronic transmission to a plurality of computing devices associated with members of the similarity audience, digital content.