Is sharing just a function of viewing? The sharing of political and non-political news on Facebook - Damian Trilling; Juhi Kulshrestha; Claes de Vreese; Denis Halagiera; Jakub Jakubowski; Judith Möller; Cornelius Puschmann; Agnieszka Stępińska; Sebastian Stier; Cristian Vaccari (Journal of Quantitative Description: Digital Media)