People developing a faceted view of data may find tFacet from VisualDataWeb helpful.
"... a new tool that applies known interaction concepts to allow hierarchical-faceted exploration of RDF data.” According to the description, “The aim is to facilitate ordinary users to formulate semantically unambiguous queries so as to support the fast and precise access to information. Used interaction concepts are e.g. a directory tree and interchangeable columns that are already well-known from other applications. The directory tree, for example, is used to enable the intuitive exploration and selection of hierarchical facets. "
Website has a short screencast and a demo.