Most of the major newsgroups have a charter, which lays down the purpose of the group and some guidelines for the discussions. This charter generally specifies the topics for discussion, any topics which are considered unacceptable, and the moderator (editor) if any. Most newsgroups are unmoderated, which means that anyone may submit messages; some, such as groups devoted to announcements or discussions relevant to a specific group, may be moderated, which means that all messages are screened and/or edited before they are submitted to the group.
The newsgroups are arranged hierarchically; there are eight major hierarchies.
|humanities:||the social sciences|
|news:||generally informative postings|
|rec:||recreation activities; sport, music, food, crafts|
|soc:||"social" newsgroups, especially those for special-interest groups and minorities|
|talk:||general chat groups|
Along with these, although less widely propagated, are the "alt" hierarchy, which is the anything-goes area of Usenet - anyone may create a group to discuss anything at all - and the "biz" hierarchy, which is the best place to post commercial advertising. Some other hierarchies exist, most of which are specific to a region or to a particular Internet provider.
is a group about setting up Microsoft Windows (comp = computer group, os = operating system-related),
is a group for business to post advertisements about sales of PC-related hardware and software, and
is a group for cat-owners and cat-lovers to swap tips and stories.
There are many groups that include "forsale" or "marketplace" within their names, which will tolerate varying amounts of commercial advertising. Hype or overblown ads are the quickest way to turn people off; the best idea is to post a short, informative announcement about your service or product, and an email or Web address where people can find out more.