The OCLC CONTENTdm Metadata Working Group was formed in response to research demonstrating the need for guidelines and best practices for creating quality Dublin Core metadata, which is useful to the primary user community, but also “shareable” outside of the local context. The CONTENTdm Metadata Working Group has worked since August 2009 in a test environment to identify best practices for creating Dublin Core metadata in CONTENTdm and mapping to MARC for sharing in WorldCat.org via the WorldCat Digital Collection Gateway, a self-service OAI harvesting tool. The first best practices document identified 12 core metadata fields and four recommended fields “as appropriate,” and provides guidelines for field content standardization and mapping. Concerns such as adherence to the Dublin Core one-to-one principle and the recording of original and digital dates and publishers are discussed, along with recommendations for configuring metadata for the Digital Collection Gateway, which was developed to increase the shareability of metadata.