Below the Radar: Private Groups, Locked Platforms, and Ephemeral Content—Introduction to the Special Issue:

This special issue of Social Media + Society originates from the first AoIR Flashpoint Symposium, entitled "Below the Radar: Private Groups, Locked Platforms and Ephemeral Content." The aim of this conference was to investigate platform-driven changes and emerging practices of everyday-life content production occurring "below the radar" of internet research, or outside of previous standards of data visibility and accessibility on which most internet studies have been based over the last decade. In the current context, online spaces seem to be heading toward more circumscribed and unsteady forms of publicness, which contrast with the platform affordances upon which the theorization of networked publics has been built. Private groups, locked platforms, and ephemeral contents are some of the challenges that require the development of new perspectives and research tools capable of adapting to this shifting environment. In this introduction, we will illustrate how the theme of "below the radar" has evolved since the initial call thanks to the confrontation with the researchers who participated in the conference, and this special issue, and we will introduce the nine articles that make up the collection. These articles, which combine different research disciplines and techniques, provide a map of some of the most urgent theoretical, ethical, and methodological issues concerning the current transformations of the visibility regimes of online social action