The National Information Standards Organization has released a draft of the Open Discovery Initiative: Promoting Transparency in Discovery.
Here's an excerpt from the announcement:
Launched in 2012, the NISO Open Discovery Initiative (ODI) aims to facilitate increased transparency in the content coverage of index-based discovery services and to recommend consistent methods of content exchange. This draft recommended practice provides specific guidelines for content providers on metadata elements, linking, and technical formats, and for discovery service providers on content listings, linking, file formats, methods of transfer, and usage statistics. The document also provides background information on the evolution of discovery and delivery technology and a standard set of terminology and definitions for this technology area.