Natural presence is distinct and grounds ethical behaviour in one's own, as well as other people's, survival. Mediated presence can provide vital information and significant communication. Through social interaction, witnessed mediated presence may contribute to taxonomies of communities of practice. The dynamics of witnessed presence create grounds, rightly or wrongly, for trust to build up or to break down. Witnessed presence in mediated communication does not trigger a sense of responsibility and respect for human dignity in the way that this happens in natural presence.