The newsgroups are organised in a hierarchical tree, each level separated by a dot. The top level is called a category.
The [original] USENET News are made out of 7 categories/groups (based on [][p. 154]EK:UNIX). Table 13.3 displays those categories.
Table 13.3: USENET News Categories.
But since any newsgroup may be created locally and be distributed to all other news servers, a number of other categories are now accessible by most sites.
The most important other categories are (based on [p. 155-6]EK:UNIX) shown in table 13.4.
Table 13.4: Other important Network News Categories.
Any newsserver may chose which groups are allowed on the system. NRC only has a subset of those groups on the main newsserver, , in addition to many other categories, some of which are seen in 13.5.
Table 13.5: More Local Network News Categories.