More than 130 years after Karl Marx's death and 150 years after the publication of his opus magnum Capital: Critique of Political Economy, capitalism keeps being haunted by period crises. The most recent capitalist crisis has brought back attention to Marx's works. This volume presents 16 contributions that show how Marx's analyses of capitalism, the commodity, class, labour, work, exploitation, surplus-value, dialectics, crises, ideology, class struggles, and communism, help us to understand the Internet and social media in 21st century digital capitalism.