Abstract from downloadable PDF: Data on the Semantic Web is semi-structured and does not follow one fixed schema. Faceted browsing is a natural technique for navigating such data, partitioning the information space into orthogonal conceptual dimensions.
Piggy Bank can collect “pure” information in the following cases: The web page has invisible link(s) to RDF data (encoded in RDF/XML or RDF/N3 formats). One of Piggy Bank's "screen scrapers" matches the current URL. A screen scraper is small Javasc