In recent academic and public debates the rise of populism has been related to digital media, as they allow populist actors to bypass the mainstream media and directly reach citizens. However, because of measurement issues it remains unclear (1) whether there is significant exposure to populist online communication, (2) how exposure is related to individual-level variables and (3) whether the political context matters. We address these questions by combining surveys and observational web tracking data for France, Germany, Italy, Spain and the U.S. This original data allows us to precisely measure and link online media exposure to individual-level attributes, political behavior and attitudes. For each country, we identify populist communication by compiling domains attributed to populist politicians and parties and labeling populist communication in the most visited political URLs. Tracking participants' browsing behavior over several months and surveys conducted before and after the 2019 European Parliament election campaign allow us to describe the prevalence of exposure to populist online communication and test hypotheses on its individual-level antecedents across countries.
