You may have heard the term "linked data." A Google search for linked data will return a myriad of search results where you can read about linked data in detail. However, I will attempt a very brief definition here: Linked data is a way to publish data on the web in a standard format that can be easily processed by computers, and that expresses the relationships between different pieces of data (or "things"). When data is published as "linked data," computers can analyze information from linked data sources to display and use the data in a human-readable format.
Traditional library metadata, such as bibliographic and authority records, has not been expressed as linked data in the past. This makes it challenging for library metadata to be used on the web outside of library-related websites (such as OPACs). Displaying library metadata to users who start their searches outside of library-related websites can bring users to libraries who might not have considered the library as a resource in their search.
In order to transform library metadata into linked data, much back-end work is necessary. Large library organizations, such as OCLC, the Library of Congress, and large academic libraries have been working to transform library metadata into linked data and provide resources that the wider library community can use.
To learn more about library linked data projects, check out the following (this is by no means an exhaustive list):
For a brief (15-minute) introduction to linked data and its applications for libraries, see the OCLC video, Linked Data for Libraries. For a technical explanation of OCLC's linked data work, see Library Linked Data in the Cloud, available for loan via the SCLS Professional Collection.