HelpThing and WikiThing
Discussion of the HelpThing and WikiThing features.
HelpThing is an editable, member-written, contextual help for LibraryThing's features, concepts and culture. Each time you click on a Help link such as the one on the top-right of every page, it takes you to a related page in HelpThing. HelpThing can refer both to the HelpThing namespace in the wiki as well as tagging wiki topics {{HelpThing}} to index them in the site-wide HelpThing search.
WikiThing is a community space that goes beyond HelpThing and provides a home for all sorts of personal and community projects that revolve around books and libraries. It also provides a place for more extended discussion of concepts and site-related features rather than just the HelpThing pages that are linked to from each page.