Speech act theory mainly tries to account for the linguistic encoding of communicative intentions in context. Given the ever growing importance of communication technologies in public and everyday spaces, however, one needs to comprehend how media affordances and human mediation agents influence speaker communicative intention diffusion in public discourse.This paper shows how the mediated conditions of modern public discourse alter the ways in which speech acts are performed, interpreted and processed in public arenas. Mediated speech acts' performativity stretches beyond affecting interlocutor relations locally. They have the sort of power that Austin originally allocated to performatives in ritualistic contexts, as well as the power to alter relationships (in terms of power and hierarchy) between one and many, between many and one and between many and many, as in the case of collective speech acts (see Meijers 2007). The paper considers two modes of mediation – journalistic and technological – as an introduction to a wider discussion of performativity in media settings and of possible paths of mediated speech acts analysis. It concludes by outlining the fitness of examining mediated speech acts for both linguistic pragmatics and media research. It is argued that a detailed, balanced analysis of speech act realization, interpretation and processing in public arenas, together with social, political and cultural theories of communication, can increase our comprehension of how speech acts create and are created by public and mediated contexts.