Political advertising on social media: Issues sponsored on Facebook ads during the 2019 General Elections in Spain

Facebook's advertising platform provides political parties with an electoral tool that enables them to reach an extremely detailed audience. Unlike television, the sponsored content on Facebook is seen only by the targeted users. This opacity was an obstacle to political communications research until Facebook released advertiser-sponsored content in 2018. The company's new transparent policy included sharing metadata related to the cost and number of impressions the ads received. This research studies the content sponsored on Facebook by the five main national political parties in Spain during the two General Elections held in 2019. The research corpus consists of 14,684 Facebook ads. An extraction algorithm detected the key terms in the text-based messages conveyed in the ad. The prominence of these topics was estimated from the aggregate number of impressions accumulated by each term. Different content patterns were assessed following three categories: user mobilization, candidate presence, and ideological issues. PSOE and PP positioned themselves more toward calls to action. Podemos had the greater number of issues related to policy among the most salient topics in its advertising. Ciudadanos' strategy focused more on its candidate and mobilization. Vox sponsored few Facebook ads, and they barely included policy issues. Spain was a highly prominent term in all parties' campaigns. Ciudadanos shared the middle ground on the ideological axis: they promoted social issues more aligned with left-wing parties as well as economic topics usually advocated by the right-wing. Overall, our results point to a greater emphasis on candidates rather than issues.