  The openness and accessibility of the Web has contributed greatly to its
worldwide adoption. Uniform Resource Identifiers (URIs) are used for resource
identification on the Web. A resource on the Web can be described in many ways,
which makes it difficult for a user to find an adequate representation. This
situation has motivated fruitful research on content negotiation to satisfy
user requirements efficiently and effectively. We focus on the important topic
of content negotiation, and our goal is to present the first comprehensive
state of the art. Our contributions include (1) identifying the characteristics
of content negotiation scenarios (styles, dimensions, and means of conveying
constraints), (2) comparing and classifying existing contributions, (3)
identifying use cases that the current state of content negotiation struggles
to address, (4) suggesting research directions for future work. The results of
the state of the art show that the problem of content negotiation is relevant
and far from being solved.
