  This paper deals with the hot, evergreen topic of the relationship between
privacy and technology. We give extensive motivation for why the privacy debate
is still alive for private citizens and institutions, and we investigate the
privacy concept. This paper proposes a novel vision of the privacy ecosystem,
introducing privacy dimensions, the related users' expectations, the privacy
violations, and the changing factors. We provide a critical assessment of the
Privacy by Design paradigm, strategies, tactics, patterns, and
Privacy-Enhancing Technologies, highlighting the current open issues. We
believe that promising approaches to tackle the privacy challenges move in two
directions: (i) identification of effective privacy metrics; and (ii) adoption
of formal tools to design privacy-compliant applications.
