Lipschitz free spaces and actions on $l^1$

This talk will be devoted to the class of uniformly Lipschitz affine group actions on the Banach space $l^1$. After discussing the motivations for studying such actions, I will concentrate on the notion of Lipschitz free Banach space, and explain how it is useful for constructing actions on $l^1$ for various classes of groups, including hyperbolic groups, mapping class groups, and 3-manifold groups.