  The Open Archives Initiative (OAI) was created as a practical way to promote
interoperability between eprint repositories. Although the scope of the OAI has
been broadened, eprint repositories still represent a significant fraction of
OAI data providers. In this article I present a brief survey of OAI eprint
repositories, and of services using metadata harvested from eprint repositories
using the OAI protocol for metadata harvesting (OAI-PMH). I then discuss
several situations where metadata harvesting may be used to further improve the
utility of eprint archives as a component of the scholarly communication
infrastructure.
