On Facebook, patterns of user engagement largely shape what types of political content citizens can see on the platform. Higher engagement leads to higher visibility. Therefore, one of the major goals of political actors’ Facebook communication is to produce content with the potential to provoke user engagement, and thereby increase their own visibility. This study introduces the concept of self-centered social media communication style which focuses on “salient” and “owned” issues with populist and negative appeals and investigates how user engagement is related to its main elements. We also explore how users’ receptivity to these content-related factors is shaped by country context. More specifically, we hypothesize that users are more likely to react, comment on and share posts focusing on salient topics or issues “owned” by parties rather than more permanent policy issues, and posts including populist appeals and negativity. Further, we test how these effects are moderated by geographical regions and the level of party system polarization. We manually coded 9,703 Facebook posts of 68 parties from 12 European countries in the context of the 2019 European elections. Our findings show that users are more likely to engage with immigration-related, domestic, populist and negative posts, but react less to posts dealing with environmental or economic issues. While issue ownership does not play a significant role for user engagement, country context plays a minor role. However, some populist appeals are more effective in more polarized countries.

Search engines are important political news sources and should thus provide users with diverse political information – an important precondition of a well-informed citizenry. The search engines’ algorithmic content selection strongly influences the diversity of the content received by the users – particularly since most users highly trust search engines and often click on only the first result. A widespread concern is that users are not informed diversely by search engines, but how far this concern applies has hardly been investigated. Our study is the first to investigate content diversity provided by five search engines on ten current political issues in Germany. The findings show that sometimes even the first result is highly diverse, but in most cases, more results must be considered to be informed diversely. This unreliability presents a serious challenge when using search engines as political news sources. Our findings call for media policy measures, for example in terms of algorithmic transparency.

Social media (SM) are often regarded drivers of personalized echo chambers in which only ideas resonante that individuals already hold, leading to more extreme opinions and intensified opinion expression. However, recent theorizing and evidence has cast doubts on the universal applicability of the echo chamber metaphor, pointing out that communication effects on opinion expression are much more complex than the metaphor suggests. Using the refugee crisis in Germany as a background, the current study challenges four implicit premises of the echo chamber metaphor empirically. The findings show a more complex picture than the metaphor implies: (1) Ignoring other information sources beyond SM may lead to severe misinterpretations; seeming evidence for echo chambers disappears after controlling for news media use. (2) SM reliance does not generally stimulate opinion expression. (3) Attitude extremity moderates the effect of SM reliance, suggesting that people with more extreme views are susceptible to echo chamber effects. (4) Attitude position on the issue-at-hand moderates the effect of SM reliance, which suggests that echo chambers do not completely shield their users from the public discourse. We propose the Echo Chamber Continuum (ECCo) Model to stimulate developing the echo chamber metaphor into a theory suitable for studying opinion formation.

The diversification of information sources has reignited the controversy on media-induced fragmentation endangering social integration. The media's capability to set the public agenda and create issues as a common core is a pivotal part of the public sphere and contributes fundamentally to society's cohesion. Algorithm-driven sources like social media that personalize content to the preferences of individuals and their social networks are considered agents of fragmentation of the public sphere. Politically extreme individuals relying on them may be particularly vulnerable to losing touch with society's common core. We employ an innovative operationalization of fragmentation on the individual level: “issue horizons”—comprising issue diversity, top issue focus, and issue overlap—to investigate how different information sources affect fragmentation. In a two-week daily diary, conducted 2016 in Germany, 356 participants named the two most important political issues of each day and reported the issue-specific sources of information. Results show that social media reliance neither increases nor decreases the compatibility of individuals' issue horizons, but news media reliance significantly increases the compatibility of issue horizons among the politically more extreme. Not relying on news media (but rather on social media) means that politically extreme persons are at risk of losing touch with society's mainstream. This attests to the news media's ongoing, indispensable integration function. Using multiple sources of political information—including the news media—appears to be of paramount importance in ensuring that most citizens are aware of the most important issues facing the nation.

By providing diverse news content, news media are key for a well-functioning public sphere. However, agreement on how to measure news content diversity is lacking. Research often refers to democratic theory as normative reference point, but different models of democracy understand news content diversity differently. Our study makes a unique, innovative contribution to this field: (1) We develop a methodological framework for measuring news content diversity, that is a set of comprehensive measuring instruments that derive different operationalizations of topic and actor diversity each from liberal and deliberative democratic theories. (2) Considering that a good public discourse requires more than diversity, we analyze news content diversity in the context of four other journalistic standards: neutrality, rationality, discursivity, and civility. (3) We prove the applicability of our measuring instruments by means of a standardized content analysis of six German news media as a case study. The different quality profiles of these outlets our analysis reveals are explained by their different functions in the media system. Our study shows how important a multi-perspectival normative approach to news content diversity is, both empirically and theoretically. Future studies on news content diversity should make their normative foundations transparent and derive their indicators purposefully therefrom.

Politicians can use social media to prompt citizens to engage by means of calls to action—statements, often in imperative form, that explicitly encourage audiences to take immediate action. This study makes a twofold contribution to this field: (1) Theoretically, we relate three factors shaping social media campaigns (audiences, affordances, genres) to calls to action related to three main campaign functions (information, mobilization, interaction). (2) Empirically, we show the applicability of this framework to systematic platform comparisons in the Western European context, taking the use of Facebook, Instagram, and Twitter by political actors in Norway as an example. Conducting a standardized manual content analysis, we find that calls for certain kinds of action are more common than others, probably related to shortage of time and resources in election campaigns. Which calls to action are used is clearly affected by the platforms on which they are published.