Once upon a time, the Internet was a "community". And someone invented a distributed bulletin board system. The easiest way to carve up a bulletin board system is by topic. What could be more logical? But at the end of the day, it doesn't work. Some of the problems are caused by the fact that the Internet is now a whole lot bigger than a community. (They say that a community has about 150 members, whereas the Internet has potentially 6000,000,000 members, or at least a reasonable fraction of that number.)
A reader of Usenet can subscribe to a newsgroup. A newsgroup has a name that specifies its topic, e.g. sci.math, which represents Mathematics. If you happen to be interested in mathematics, you might naively suppose that it would be useful to subscribe to sci.math. So you make your subscription, you start reading your messages, and you get a shock. Most of it is just rubbish. What is not rubbish is large irrelevant to your own particular interests. And if you find something interesting, it is unlikely to be worth the effort of searching for it.
The extreme version of irrelevant, low quality postings is spam. Spam consists of messages that are advertising something (usually worthless, or an outright scam), which has nothing to do with the supposed topic. Some usenet readers feel motivated to delete spam from newsgroups. Which is all very worthwhile. But the mere fact that spam is possible, and that a positive effort has to be made to get rid of it, is an indication that the design of Usenet is intrinsically flawed.
Well, never mind about that. There's not much worth reading on Usenet, but maybe you could post to Usenet? Must be millions of people who are going to read your message, if you have something important to say.
Since Usenet is hardly worth the effort of reading, at any one time, a very tiny fraction of the people interested in a given topic are bothering to read the newsgroups relevant to that topic. So hardly anyone will actually read your posting.
One proposed cure for the quality problem in Usenet is moderation. This generally amounts to some individual being assigned the job of vetting messages for posting. There are various problems with moderation -
Moderation also interferes with the topic hierarchy. Either a newsgroup is moderated or it is not, and each moderated news group is tied to a particular moderator (or set of moderators). Sometimes there are two newsgroups with different names that effectively serve as moderated and un-moderated versions of the same newsgroup.
If the names of newsgroups seem inappropriate, or a hierarchy is divided up in the wrong way, or not divided up at all, there is not a lot you can do about. Unless of course you are prepared to go to a lot of effort trying to convince others that newsgroups should be changed in some way.
One simple objection to newsgroup names is that they are somewhat non-intuitive. For example, a better name for sci.math might be Mathematics.
Dis-satisfaction with Usenet leads people to use alternatives, including -
Despite the poor quality of Usenet, it does have some features that seem desirable if they could be retained in a system that dealt with the quality problems:
These features are missing in the alternatives listed in the previous section.