Metadata schemas relevant to online education and training have recently achieved the milestone of formal standardization. Efforts are currently underway to bring these abstract models and theoretical constructs to concrete realization in the context of communities of practice. One of the primary challenges faced by these efforts has been to balance or reconcile local requirements with those presented by domain-specific and cross-domain interoperability. This paper describes these and other issues associated with the development and implementation of metadata application profiles. In particular, it provides an overview of metadata implementations for managing and distributing Learning Objects and the practical issues that have emerged so far in this domain. The discussion is informed by examples from two national education and training communities – Australia and Canada.