Abstract: A computer-implemented method and system for improving recipient response rates to content presented via a data communications network to a plurality of recipients based upon recipient response data, wherein the content comprises a plurality of content factors. Each content factor is selected from one or more corresponding content levels. A data structure is provided for containing recipient response data associated with content comprising combinations of content levels. A plurality of content samples is generated by forming combinations of content levels for a plurality of content factors in accordance with respective combination weightings derived from recipient response data contained within the data structure. The plurality of content samples is presented to a corresponding plurality of recipients via the data communications network. The recipient responses to the content samples are received via the data communications network.