Since 2016, a culture of participatory leftism has emerged on Facebook that has yet to be substantially documented. Scholars have established ideographic criticism of memes as a critical/cultural tool for analysis. However, there is little to no work on broader, systems-based analyses of alternative social media platforms, and the role they play in the creation and maintenance of political identities. These socially mediated communities, alternatively known as Leftbook (or Left Facebook), advertise themselves as places to learn about Marx, socialism and philosophies centred on labour, revolution and worker freedom. My guiding research questions are ‘[a]s platforms such as Leftbook become environmental, how do they contribute to a mode of socio-political identity construction for members of the Left?’ and ‘[a]s extensions of political identity, how does the ‘Sassy Social Memes’ page impact experiences of political organizing and engagement?’.