The political economy literature on social media has primarily focused on misinformation and polarization. We highlight a different and overlooked channel: the effect of data-driven voter profiling on politicians’ incentives to acquire policy-relevant information. We develop a model in which an incumbent politician can exert costly effort to learn about an uncertain state of the world before proposing a policy to a representative voter. The politician does not perfectly observe the voter's prior beliefs, or opinion. Improvements in voter profiling, such as those enabled by social media, correspond to reductions in this uncertainty. The politician's learning effort increases her re-election chances through two channels: a quality effect, by improving the match between the policy and the true state; and a persuasion effect, by inducing voters to place lower weight on their opinion and thereby compressing ex-post disagreement across possible voter types. We show that the higher the politician's uncertainty over the voter's opinion, the stronger her incentives to exert effort to change it. Therefore, improved voter profiling lowers equilibrium learning effort and ultimately reduces the quality of democratic representation.