educationally significant characteristics and relationships can be expressed. Learning Registry The Learning Registry (learningregistry.org), a joint project of the US Department of Defense and US Department of Education, provides an infrastructure that enables instructors, teachers, trainees and students to discover and use the learning resources held by various federal agencies and international partners. The Learning Registry enables better access to learning resources and the building of interconnected and personalized learning solutions. The Learning Registry is not another repository, search engine or portal. It is a resource distribution network with open APIs that anyone can use to expose or consume learning resources and information about how they are used. It enables building a business-to-business infrastructure where users can find, share, use and augment learning resources. Organizations build third-party applications and communities on top of the distribution network to facilitate learning resource discovery, access and sharing. These applications let communities of users publish information about learning resources or discover information about learning resources. The Learning Registry network hosts and shares both metadata and paradata (content about where a learning resource was used, comments, rankings, ratings, etc.), i.e., the Learning Registry provides “social networking for learning resources”. It combines cataloging information, usage, assertions, data exhaust and analytical data into a single, sharable timeline for learning resources.