Introduction to the special issue on social networks and ubiquitous interactions

This special issue of the International Journal on Human– Computer Studies is dedicated to Social Networks and Ubiquitous Interactions. For this special issue we invited submissions of original research exploring the interplay between online social networks and ubiquitous technologies. HCI venues have seen an increase in papers looking at online social networks, and how the rich information that users provide can be used to personalize the interaction in these systems. In addition, several research projects in the area of ubiquitous computing are aiming at inferring users' context and adapting to it accordingly. Given these trends, in this special issue we explore how the rich information in online social networks can be leveraged to adapt ubiquitous systems, and conversely how ubiquitous technologies can be used to make online social networks more interactive, and therefore, more interesting and engaging for users. Our special issue received 22 high-quality submissions. There was great diversity in the manuscripts we received, reflecting the vibrant and active community working at the intersection of social networks and ubiquitous interactions. After two rounds of reviews involving 44 reviewers we were able to select 5 manuscripts to form the special issue that we now present. These five manuscripts represent a very diverse set of research teams, including academic teams from Europe, North America, South America, and Asia, as well as two industrial players: Nokia and Google. This diversity in the topics of the manuscripts was matched by a diverse and experienced set of reviewers to whom we are grateful for donating their time.