  Over three years ago, the Core Integration team of the National Science
Digital Library (NSDL) implemented a digital library based on metadata
aggregation using Dublin Core and OAI-PMH. The initial expectation was that
such low-barrier technologies would be relatively easy to automate and
administer. While this architectural choice permitted rapid deployment of a
production NSDL, our three years of experience have contradicted our original
expectations of easy automation and low people cost. We have learned that
alleged "low-barrier" standards are often harder to deploy than expected. In
this paper we report on this experience and comment on the general cost, the
functionality, and the ultimate effectiveness of this architecture.
