You can just download the list of newsgroups. If you find one that looks interesting you can just post to it. The main issue is most unmoderated groups are ove

You can just download the list of newsgroups. If you find one that looks interesting you can just post to it. The main issue is most unmoderated groups are overrun with spam. Most news readers don't do a great job filtering that spam so for every ham post in a thread there can be dozens of spam messages. There's also effectively no enforcement of any group's etiquette so even ham messages tend to be pretty low quality. Usenet is just a message distribution mechanism. There's just a lot of small world culture around its management. It started in the era of small world Internet so that's understandable but it's definitely a quirk of the whole structure. You have to know or get to know the right people to start groups or get them carried or manage their moderation.