With the rapid development of the Web in the direction Social Media, the number of communication possibilities has increased exponentially, bringing new challenges and opportunities for companies to build and shape their reputation online as well as to engage and maintain good relations with their customers. In this paper we describe how semantic technologies enable scalable, effective and efficient on-line communication. We propose four different ways in which semantics can be used for this purpose. First, we discuss semantic analysis of communication items based on 'classical' semantics, such as natural language processing. Second, we look at semantics as a channel, viewing Linked Open Data vocabularies not only as terminological assets but as communication channels. Third, we demonstrate how semantics provide the methodologies and tools for content modeling by means of ontologies. Finally, we outline how semantics through semantic matchmaking enable semi-automatic assignment and distribution of content to channels and vice-versa.