Unlike most of the other hierarchies, there is no centralised control of the hierarchy and anyone who is technically capable of creating a newsgroup can do so. In practice, however, most newsgroups follow an informal procedure involving a public discussion in alt.config before being created. This procedure is designed to help the potential creator better understand what factors contribute to a newsgroup's success.
It is up to each individual news administrator whether to add a new newsgroup, and some will not do so if the group has not been discussed in alt.config. As a result groups that do not follow this procedure are usually not well-propagated. News group removal in theory occurs in much the same way as newsgroup creation, however as a matter of practice most news administrators do not remove newsgroups.
In particular, the creation of the talk.* hierarchy for discussions of controversial or sensitive issues by the renaming did not go well. The alt.* hierarchy was suggested as an alternative to talk.* by Brian Reid. It would be a network without the backbones, thereby free from backbones' influences on creating or not creating a new newsgroup. The first newsgroup on alt hierarchy was his alt.gourmand.
According to the "So You Want to Create an Alt Newsgroup" FAQ, the name "alt" is an acronym for "Anarchists, Lunatics, and Terrorists", though the acronym also refers to the fact that it is a "hierarchy that is 'alternative' to the 'mainstream' (comp,misc,news, rec,soc,sci,talk) hierarchy..
Alt has since become home for a wide variety of things that did not fit elsewhere. In particular, there are many alt.fan newsgroups, mostly devoted to discussions of the work and life of famous people: writers, musicians, actors and athletes have alt.fan groups. This sub-hierarchy has also been used for self-promotion by otherwise unknown people. During the notorious trial of Karla Homolka, alt.fan.karla-homolka was created to get around the Canadian news blackout on the case.
Two major sections of the alt.* hierarchy, the alt.sex.* and alt.binaries.* hierarchies, have been found to fit better in the alt.* hierarchy than the Big Seven. Because of the inevitably lurid and sometimes offensive subjects that it would cover, newsgroup administrators objected to the inclusion of one or more newsgroups covering sexual topics in the Big Seven (including the existing rec.arts.erotica), fearing that they may prevent the major news hierarchies from being widely distributed. News administrators are free to add any or all of the alt.sex.* newsgroups without having to worry about conflicting with the Big Seven. Likewise, any and all of the alt.binaries.* newsgroups can be accepted or rejected by administrators if they choose. Binaries are often of extremely large size, which is why administrators may choose to exclude them.
Several extensions of the alt.* hierarchy have become quite successful on their own. A number of newsgroups have taken advantage of the freedom of the alt.* hierarchy to create a number of newsgroups that specialize on certain topics, as opposed to the broader "generic" discussions of the Big Seven hierarchy. For instance, the rec.* hierarchy may be home to the movie discussion newsgroups rec.arts.movies.current-films, rec.arts.movies.past-films, and rec.arts.movies.reviews; but the alt.movies.* hierarchy contains more focused discussion groups including alt.movies.silent, alt.movies.hitchcock, alt.movies.kubrick, and alt.movies.visual-effects.
The language of preference in the "original" Usenet hierarchies, including alt.*, is English, which implies that the preferred character set encoding for these newsgroups is ASCII. Other language hierarchies have later been created in parallel to the existing English ones, for example de.* for German, fr.* for French, etc. Some access providers also created their own versions, prefixing the newsgroups names with their own name in a similar way. Messages posted in these "private" groups are generally not passed to other providers or the internet in general.