The Usenet is often compared with a giant blackboard on which everyone can leave messages. The Usenet operates in the same way by providing so-called newsgroups in which messages can be posted. To this extent, the newsgroups are similar to the discussion forums on the World Wide Web which enables users to post and read messages.
Newsgroups are usually devoted to one particular topic, this mostly being discernable from the name of the newsgroup. Brief descriptions, the so-called "tag lines" provide further information on the content of the newsgroup. The hierarchical structure of the Usenet is also reflected in the name of the various newsgroups.
The first block of the name of the newsgroup designates the top hierarchical level, which divides the Usenet into main topic areas. The nine main hierarchies are comp.*, talk.*, soc.*, sci.*, humanities.*, misc.*, news.*, rec.* (the so-called "Big Eight") and alt.*. Whereas the first eight groups mentioned, the "Big Eight", are subject to content monitoring, this is not the case with regard to the final group alt*. For this reason, alt.* contains a large proportion of the so-called binary newsgroups in which both messages and file attachments, the so-called binaries, are to be found.
Binary newsgroups are usually easily identified via their name. After the top hierarchical level, the second block mostly includes the term "binaries". Example: alt.binaries.* This means that these newsgroups can be used to download or publish files as well as for messages.
The binaries are easy to find and download with the help of the appropriate Usenet software, although this is usually only available from commercial Usenet providers. Conventional Usenet search engines, on the other hand, often do not permit users to search for binaries or at least make file download considerably more difficult.
Whereas the basic principle of peer-to-peer networks is to exchange files with other users – i.e. also involving making files available to other users – this is not usually expected in the Usenet. One reason for this is the enormous data load. If all Usenet users were to publish files in binary newsgroups themselves, theservers would be inundated with binaries. It is, therefore, quite legitimate for Usenet users only to download files without publishing any themselves.