  "Data" is becoming an indispensable production factor, just like land,
infrastructure, labor or capital. As part of this, a myriad of applications in
different sectors require huge amounts of information to feed models and
algorithms responsible for critical roles in production chains and business
processes. Tasks ranging from automating certain functions to facilitating
decision-making in data-driven organizations increasingly benefit from
acquiring data inputs from third parties. Responding to this demand, new
entities and novel business models have appeared with the aim of matching such
data requirements with the right providers and facilitating the exchange of
information. In this paper, we present the results and conclusions of a
comprehensive survey on the state of the art of entities trading data on the
internet, as well as novel data marketplace designs from the research
community.
