Recent scholarship on the intersections between digital media and political debate has taken on a decidedly pessimistic, even dystopian tone, and not without reason: from the effective use of social media platforms by populists and demagogues like Donald Trump to the expression of deepening ideological divides in online public debate, and from the emergence of partisan online communities and platforms to the intensification and exploitation of such partisanship by conspiracy theorists and state actors, there are substantial concerns about the way that extremist actors are utilising digital and social media logics to further their ideological agendas. The situation is further complicated by platform providers’ and regulators’ limited and unsystematic responses to these issues. But while there is considerable research into the various issues and events that illustrate these developments, many of the central concepts that are used to describe these cases receive substantially less critical attention. Terms such as ‘influence’, ‘populism’, ‘partisanship’, and ‘polarisation’ are often deployed as if did not themselves require further qualification and definition – even in spite of the considerable volume of literature in political science and other ancillary disciplines that addresses the various facets that such concepts may have. Informed by and building on substantial empirical research, this panel therefore facilitates a conversation between methodological innovation at the coalface of digital trace data analysis and careful reflection on the definitions of key concepts, in order to explore the conceptual frameworks and methodological approaches that might illuminate the distinct features of our four key concepts in sharper focus. Our first paper engages with the concept of influence, which it conceptualises as the power to affect others. Focussing especially on the spread of verified false content (VFC) through social media, it proposes a novel population-scale approach that both employs a bottom-up perspective for identifying the influential actors spreading such content, and highlights the exposure of ordinary citizens to these messages. It demonstrates this approach by drawing on the large-scale Facebook URL-sharing dataset available from Social Science One, developing an EU-wide perspective on VFC exposure at national levels. Our second paper continues this approach by critiquing the concept of populism, highlighting the term as a weak analytical concept. It argues that, rather than focussing on their populist stance, populist politicians can be judged by the extent of their delegitimising rhetoric. Further, the paper asserts that such rhetoric is enabled by the decentralised communication environment of social media. The utility of the concept of delegitimisation is that enables the identification of political messages that are truly dangerous because they are meant to destabilise fundamental democratic principles, such as the integrity of the vote and the legitimacy of alternative policy perspectives. By situating this in the context of social media messaging, we can see how such messages are amplified by distributed network channels. Our third paper shifts focus to the possible results of influence campaigns and populist demagoguery, and addresses the concept of partisanship. Taking as case study the 2022 Italian election, it introduces a novel combination of computationally informed analytical methods and applies them to social media data to gauge the level of partisan attention devoted to the different news sources and political topics in the election campaign, and distinguish between partisan and cross-partisan sources and themes. This provides new insights into the structures, intersections, and faultlines of partisanship, and enables the mapping of a broader multi-dimensional ideological space. Our final paper continues this discussion by exploring the complexities of polarisation. It highlights the conceptual fluidity of this term, which is expressed in the multitude of adjectives and qualifiers that can be found in the relevant literature – from ideological through affective to interactive polarisation and beyond, and from benign and even beneficial to pernicious and destructive polarisation. Mapping these distinct forms of polarisation onto a diverse range of mixed-methods digital media research approaches, and outlining a number of criteria for assessing whether the dynamics of polarisation have turned destructive, it outlines new pathways for polarisation research in Internet studies. In combination, then, these four papers offer a timely nudge for digital and social media research to revisit and reconsider some of the central concepts in online political communication studies, and to retrace and reaffirm the connections between the definitions of these concepts and the methodological frameworks that we use to study them.