This document discusses the differences between traditional controlled vocabularies used in library cataloging systems and social tagging by users. Controlled vocabularies provide authoritative, structured hierarchies but require subject expertise, while tags are more intuitive and provide additional access points, but quality and specificity can vary. The document argues that an integration of both systems, using tags to supplement controlled vocabularies, can best balance their strengths and weaknesses to increase access. It provides Library of Congress subject headings and LibraryThing tags as examples and notes that LibraryThing is currently used by over 1,500 libraries, including several in New Jersey.