This chapter discusses how campaigns target voters in various ways, from broadly targeting general groups to geo-targeting areas based on how they voted in the past. It focuses on development in American elections. The chapter reviews how campaigns use data on viewer characteristics of certain television programs, or show genres, to target more precisely a desired audience with their 30-second ads. All of these advances in the use of technology by campaigns are attempts to allocate resources more efficiently, and there is much to like about these developments from the standpoint of campaigns. The chapter also discusses these long-standing approaches to finding potential votes to a discussion of more recent techniques that involve more finely grained targeting of specific individuals based on extensive data analysis. It concludes with raising some concerns about these developments, asking the reader to speculate further on what harm can come from such extensive data mining.