The document discusses different types of library and information networks:
1. Search service networks that allow users to search databases but not modify records or output.
2. Customized service networks that allow users to search, modify records for local use, and obtain printed and machine-readable products for their data.
3. Service center networks that provide training, consulting, and planning rather than direct automated services.
It also discusses trends in networking, such as vendors expanding services to new areas and interfaces between stand-alone systems and subnetworks that will eventually connect to a national network. As technology improves, more activities will be supported at regional and local levels through a distributed national database.