This standard identifies categories for basic library statistical data reported at the national level, and provides associated definitions of terms. In doing so it deals with the following areas: reporting unit and target population, human resources, collection resources, infrastructure, finances, and services. In addition, the standard identifies new measures associated with networked services, databases, and performance. These measures are reported at a variety of levels, and at the time of this writing were slowly being incorporated into national library statistical data reports.

This system is in use for sharing marine metadata.

Some background from the ESRI Canada - Spatial Data Infrastructure Monthly Newsletter:

Z39.50 is a client-server protocol for searching and retrieving information from remote computer databases, which was developed before the arrival of the Internet. The protocol is defined by ANSI standard Z39.50, and ISO standard 23950. The Z39.50 protocol is widely used in library environments and it supports a number of actions, including search, retrieval, sort, and browse. The syntax of the Z39.50 protocol allows for complex queries. In the geospatial world, Z39.50 was used to develop an application profile for the U.S. Federal Geographic Data Committee's (FGDC) Content Standard for Digital Geospatial Metadata. This allows Z39.50 to be used to facilitate the discovery, query, retrieval, and presentation of geospatial metadata and the referenced spatial data from disperse systems that support the Z39.50 Application Profile for Geospatial Metadata. For more information on the Geo-profile see: http://www.fgdc.gov/standards/projects/GeoProfile