Recommendations

Libraries should embrace the web of information, both by making their data available for use as Linked Data and by using the web of data in library services. Ideally, library data should integrate fully with other resources on the Web, creating greater visibility for libraries and bringing library services to information seekers. In engaging with the web of Linked Data, libraries can take on a leadership role grounded in their traditional values of managing resources for permanence, describing resources on the basis of rules, and attending to the needs of information seekers.

For library leadership

Identify sets of data as possible candidates for early exposure as Linked Data

A very early step should be the identification of high-priority, low-effort Linked Data projects. By its very nature, Linked Data facilitates an incremental approach to making data available for use on the Web. The data environments of libraries are complex, attempting to expose that complexity as Linked Data all at once would probably not be successful. However, some library resources lend themselves to publication as Linked Data without disrupting current systems and services. Among these are authority files (whose members identify things) and controlled lists. Identification of such "low-hanging fruit" will allow libraries to quickly expand their presence in the Linked Data cloud without changing their workflows elsewhere.

Foster a discussion about Open Data and rights

In defining rights for data, rights owners must consider the impact of usage restrictions, as restrictions only complicate the re-use of data in a Linked Data environment. It makes sense for library leaders to seek agreement with owners about rights and licensing at the level of library consortia or even on a national or international scale. (For an example, see the Rights and Licensing section of the Open Bibliographic Data Guide for UK higher-education libraries.)

For standards bodies and participants

Increase library participation in Semantic Web standardization

If Semantic Web standards do not support the translation of library data with sufficient expressivity, the standards can be extended. For example, if Simple Knowledge Organization System (SKOS), a standard used for publishing knowledge organization systems as Linked Data, does not include mechanisms for representing the components of pre-coordinated subject headings, implementers should consider devising solutions that extend its basic elements, e.g., using the OWL Web Ontology Language. In order to ensure that these new structures will be understood by consumers of Linked Data generally, implementers should collaborate with the Semantic Web community both to ensure that the proposed solutions are compatible with current best practice and to maximize the applicability of their work outside the library environment. Members of the library world should contribute in standardization efforts of relevance to libraries, such as the W3C efforts to extend RDF to encompass the concept of provenance, by joining technical working groups or participating in public review processes. A W3C Community Group could also play an important role in this area.

Develop library data standards that are compatible with Linked Data

Semantic Web technologies conceptualize data in a way that fundamentally differs from the conceptualization underlying the data formats of the twentieth century. Linked Data is primarily about meaning and meaningful relationships between things, while traditional library data formats conflate the meaning of data and the structured encoding of data into a single package. The inseparability of meaning from encoding in formats results in less flexibility for obtaining value from an investment in data. Since the introduction of MARC formats in the 1960s, digital data in libraries has been managed predominantly in the form of "records" -- bounded sets of information stored in files of a precisely specified structure. The Semantic Web and Linked Data, in contrast, structure data as graphs -- constructs which, in principle, may be boundless. The difference between these two approaches means that the process of translating library standards and datasets into Linked Data is not trivial and must be undertaken with knowledge of new principles of data design. There is a need for best-practice documentation and recipes to guide participants in library-world standardization efforts in the construction of ontologies and structured vocabularies.

Develop and disseminate best-practice design patterns tailored to library Linked Data

Design patterns allow implementers to build on the experience of predecessors. Traditional cataloging practices have been documented with a rich array of patterns and examples, and best practices are starting to be documented for the Linked Data space as a whole such as Linked Data: Evolving the Web into a Global Data Space and Linked Data Patterns. Application profiles provide a method for a community of practice to document and share patterns of using vocabularies and constraints for describing specific types of resources. What is needed are design patterns specifically tailored to the requirements of library Linked Data. Such design patterns would meet the needs of people and developers who understand new techniques through patterns and examples as well as increase the coherence of library Linked Data overall.

For data and systems designers

Design and test user services based on Linked Data capabilities

Linked Data could ultimately lead to new and better services to users as well as enabling implementers outside of libraries to create applications and services based on library data. It is too early to predict what new types of services may be developed for information discovery and use. Experimental services using library Linked Data should be undertaken in order to explore potential use cases and inform the direction of larger development efforts.

Create URIs for the items in library datasets

Library data cannot be used in a Linked Data environment without having Uniform Resource Identifiers (URIs) both for specific resources and for library-standard concepts. The official owners of resource data and standards should assign URIs as soon as possible, since application developers and other users of such data will not delay their activities, but are more likely to assign URIs themselves, outside of the owning institution. When owners are not able to assign URIs in good time, they should seek partners for this work or delegate the assignment and maintenance of URI to others in order to avoid the proliferation of URIs for the same thing and to encourage the re-use of URIs already assigned.

Agencies responsible for the creation of catalog records and other metadata, such as national bibliographies, are the logical organizations to take a leading role in creating URIs for their described resources.

Develop policies for managing Linked Data vocabularies and their URIs

Organizations and individuals who create and maintain URIs for resources and standards will benefit if they develop policies for the namespaces used to derive those URIs. Such "namespace policies" encourage a consistent, coherent, and stable approach which improves effectiveness and efficiency and provides quality assurance for users of URIs and their namespaces. Policies might cover:

• Patterns used to coin the URIs, preferably based on best-practice guidelines.
• Institutional commitments to the persistence of the URIs.
• Version control for a vocabulary and its terms.
• The use of "HTTP" URIs, which invoke the Hypertext Transfer Protocol supported universally by Web browsers, and their resolution to any Web pages or machine-readable representations which document the meaning of the URIs.
• Extensibility of the vocabulary by other organizations.
• Translations of labels and other annotations into other languages.

Express library data by re-using or mapping to existing Linked Data vocabularies

In order to maximize linkability with other datasets, library datasets must be expressed using Linked Data terms -- properties, classes, and instances -- that have well-defined relationships to those used in the wider Linked Data space. This can be done in two ways: by using Linked Data vocabularies based on existing standards, such as ISO language names; and by defining explicit relationships ("alignments") between the Linked Data terms of the library world and those of other communities.

For librarians and archivists

Preserve Linked Data element sets and value vocabularies

Many Linked Data vocabularies are essentially cultural reference works, giving authoritative information about people, places, events, and concepts within regional, national, or international contexts. As such, preservation of Linked Data vocabularies is a natural, and essential, extension of the activity of memory institutions. Linked Data will remain usable twenty years from now only if its URIs persist and remain resolvable to documentation of their meaning. As keys to the correct interpretation of data, both now and in the future, element sets and value vocabularies are particularly important as objects of preservation. This situation presents libraries with an important opportunity to assume a key role in supporting the Linked Data ecosystem.

Apply library experience in curation and long-term preservation to Linked Data datasets

Much of the content in today's Linked Data cloud is the result of ad-hoc, one-off conversions of publicly available datasets into RDF and is not subject to regular accuracy checks or maintenance updates. With their ethos of quality control and commitment to long-term maintenance, libraries have a significant opportunity to take a key role in the important (and hitherto neglected) function of curating Linked Data, as an extension of their existing mission. By curating and maintaining as truly linkable objects the resources described within datasets, libraries can reap the benefits of opening their data for value-added contributions from other communities. Adding links to data from biographers or genealogists, for example, could enrich library resource descriptions in areas to which librarians traditionally do not themselves attend, greatly improving the possibilities for discovering and navigating their collections.