  Milgram's reality-virtuality continuum applies to interaction in the physical
space dimension, going from real to virtual. However, interaction has a social
dimension as well, that can go from real to artificial depending on the
companion with whom the user interacts. In this paper we present our vision of
the Reality-Artificiality bidimensional Continuum (RAC), we identify some
challenges in its design and development and we discuss how reliable
interactions might be supported inside RAC.
