  Data has been increasingly recognized as a critical factor in the future
economy. However, constructing an efficient data trading market faces
challenges such as privacy breaches, data monopolies, and misuse. Despite
numerous studies proposing algorithms to protect privacy and methods for
pricing data, a comprehensive understanding of these issues and systemic
solutions remain elusive. This paper provides an extensive review and
evaluation of data trading research, aiming to identify existing problems,
research gaps, and propose potential solutions. We categorize the challenges
into three main areas: Compliance Challenges, Collateral Consequences, and
Costly Transactions (the "3C problems"), all stemming from ambiguity in data
rights. Through a quantitative analysis of the literature, we observe a
paradigm shift from isolated solutions to integrated approaches. Addressing the
unresolved issue of right ambiguity, we introduce the novel concept of "data
usufruct," which allows individuals to use and benefit from data they do not
own. This concept helps reframe data as a more conventional factor of
production and aligns it with established economic theories, paving the way for
a comprehensive framework of research theories, technical tools, and platforms.
We hope this survey provides valuable insights and guidance for researchers,
practitioners, and policymakers, thereby contributing to digital economy
advancements.
