At the beginning of the 21st century, most service companies maintain relationships with their customers without any face to face communication. Companies are increasingly looking for solutions to raise personal contact with their customers while keeping a high efficiency level. Social Presence means that people can feel like being together even when their conversation is technology-mediated. We build upon Adaptive Structuration Theory to explain under which conditions the highest levels of Social Presence can be achieved. Surveys and (field) experiments are combined (1) to develop a powerful measurement instrument for Social Presence, (2) to research in which situations technology-mediated communication is perceived to be the most “personal” and (3) whether Social Presence can account for higher levels of relationship building.