DMOZ (from directory.mozilla.org, an earlier domain name) is a multilingual open-content directory of World Wide Web links. The site and community who maintain it are also known as the Open Directory Project (ODP). It is owned by AOL but constructed and maintained by a community of volunteer editors.
DMOZ uses a hierarchical ontology scheme for organizing site listings. Listings on a similar topic are grouped into categories which can then include smaller categories.