ResourceSync — a joint effort of NISO and the Open Archives Initiative (OAI) team with work funded by the Sloan Foundation — has published a draft specification that I urge members of the library technology community to look at. Building on the OAI-PMH strategies for synchronizing metadata, this project is modern web architecture technologies to enable the synchronization of the objects themselves, not just their metadata. From the abstract of the draft specification:

This ResourceSync specification describes a synchronization framework for the web consisting of various capabilities that allow third-party systems to remain synchronized with a server’s evolving resources. The capabilities can be combined in a modular manner to meet local or community requirements. The specification also describes how a server can advertise the synchronization capabilities it supports and how third party systems can discover this information. The specification repurposes the document formats defined by the Sitemap protocol and introduces extensions for them.