In "global" part of Usenet (the "big eight" groups), the newsgroup creation starts with RFDs (Request for Discussion) posted to news.groups newsgroup, in which the group's charter and rules get straightened.
After people agree (mostly) of the group rules and scope, CFVs (Calls for Votes) are sent, twice. These CFVs have the above-mentioned charter and group description. Votes are collected via E-mail by votetaker.
After some time, results of the CFVs are revealed (along with lists on who voted on what) - and if the majority thinks the group should be created, it gets created.
This process, or similiar, are also used in some regional hierarchies. This process isn't in use in alt.* hierarchy where anyone can create a group (though it's often polite to discuss about it in alt.config first).