Tobias Matzner is professor for “Media, Algorithms, and Society“ at the department of media studies at Paderborn University in Germany. His work combines theories of (digital) media and technologies with approaches from social theory, cultural studies, and political philosophy. This keynote lecture takes place in the context of the Graduate Workshop “Sisterhood on Twitter? ICT-based Collective Action and Narratives of Solidarity and Justice” on February 18, 2019, and is organized by Ms. Laura Schelenz, University of Tübingen, laura.schelenz@uni-tuebingen.de, and Mr. Tommaso Trillò, University of Lodz, tommaso.trillo@uni.lodz.pl.