Information collection and discovery tasks involve aggregation and manipulation of information resources. An information resource is a location from which a human gathers data to contribute to his/her understanding of something significant. Repositories of information resources include the Google search engine, the ACM Digital Library, Wikipedia, Flickr, and IMDB. Information discovery tasks involve having new ideas in contexts of information collecting. The information one needs to collect is large and diverse and hard to keep track of. The heterogeneity and scale also make difficult writing software to support information collection and discovery tasks. Metadata is a structured means for describing information resources. It forms the basi...