The concept is based on using IANA-registered link relation types to establish coarse-grained interoperability among scholarly communication and research nodes.
By using typed links in HTTP link headers, Signposting shows machines the way to obtain information from repeatedly occurring scenarios in scholarly portals. For examples, it helps machines find the authors of a publication, the bibliographic metadata that describe a publication, and discover the (compound) resources that make up a publication.
Signposting principles have found early adopters in DataCite, Pangaea, DANS, and the University College Dublin Digital Library. Signposting is not a formal standardization effort. It's just an accumulation of ideas from people that have spent a lot of time thinking about the web and scholarly communication on the web, working on specifications to improve on the interoperability status quo, and witnessing some specifications being adopted and others not. Those scarce resources, you know.

The Signposting approach is fully aligned with hypermedia (REST, HATEOAS) lines of thinking regarding web interoperability. Implementation of a pattern should be straightforward and would help machines significantly. Which would allow the emergence of new applications that make the life of a reader easier. Meaning great Return On Investment
Some background material related to the Signposting effort:
- Van de Sompel, H., and Nelson, M.L. (2015) Reminiscing About 15 Years of Interoperability Efforts. D-Lib Magazine, 21(11/12). DOI: 10.1045/november2015-vandesompel
- Van de Sompel, H., Rosenthal, D., and Nelson, M.L. (2016) Web Infrastructure to Support e-Journal Preservation (and More). Arxiv preprint. arXiv: 1605.06154
- Van de Sompel, H., and Nelson, M.L. (2015) Achieving Meaningful Interoperability for Web-Based Scholarship.