The book offers a social semiotic take on contemporary communication, by providing a thorough description of video-interaction, a new form of communication started on YouTube thanks to the introduction of the ''Video Response'' option. A multimodal analysis of over 2,000 videos responding to one another explores the affordances of the medium and the way these are used creatively in the interactants'' practices. It highlights how, in contemporary sign-making practices, traditional patterns of coherence are often disregarded and successful communication is driven by new principles, as the result of representations produced through the selection, copy-and-paste and recontextualization of other texts. The book offers insights to those interested in communication, language and semiotics. At an empirical level, its original contribution consists in providing a description of a new form of communication. At a theoretical level, it highlights the inadequacies of traditional theories to the description of contemporary forms of communication and points to new analytical tools that seem more apt to the task.