  Since the advent of mobile devices, both end-users and the IT industry have
been longing for direct device-to-device (D2D) communication capabilities,
expecting new kinds of interactive, personalized, and collaborative services.
Fifteen years later, many D2D solutions have been implemented and deployed, but
their availability and functionality are underwhelming. Arguably, the most
widely-adopted D2D use case covers the pairing of accessories with smartphones;
however, many other use cases-such as mobile media sharing-did not progress.
Pervasive computing and cyber-physical convergence need local communication
paradigms to scale. For inherently local use cases, they are even more
appealing than ever: eschewing third-parties simultaneously fosters
environmental sustainability, privacy and network resiliency. This paper
proposes a survey on D2D communication, investigates its deployment and
adoption, with the objective of easing the creation and adoption of modern D2D
frameworks. We present the results of an online poll that estimates end-users'
utilisation of D2D processes, and review enabling technologies and security
models.
