  Many applications need up-to-date copies of collections of changing Web
resources. Such synchronization is currently achieved using ad-hoc or
proprietary solutions. We propose ResourceSync, a general Web resource
synchronization protocol that leverages XML Sitemaps. It provides a set of
capabilities that can be combined in a modular manner to meet local or
community requirements. We report on work to implement this protocol for
arXiv.org and also provide an experimental prototype for the English Wikipedia
as well as a client API.
