Newsgroup HierarchyA Newsgroup Hierarchy is the organized structure newsgroups are sorted into for easy location and classification. The broadest of these hierarchies are known as top-level hierarchies (or big 8), examples being comp.* (computers), sci.* (science), and rec.* (recreation). Within these hierarchies are more specific sub-hierarchies. comp.programming is a newsgroup related to computer programming, for example. It is also a hierarchy, because there are newsgroups for more specific programming discussions that branch from that group. Giganews provides full access to over 110,000 newsgroups.
Giganews' Newsgroup Hierarchy Listing"