This is annecdata - not a serious academic study. Adjust your expectations accordingly.
When I first got online, the World Wide Web was still in its infancy - so CompuServe was my gateway to the Internet. I loved their well organised chat room. A couple of clicks and I could be discussing Babylon 5 with people in another country, downloading wallpapers, and uploading my poor attempts at fan-fiction. Magical.
At some point, I discovered Usenet and its decentralised collection of newsgroups. This required downloading, installing, and configuring an NNTP client. Quite the world away from CompuServe's shiny software delivered on a free CD. But I persevered and, by the time I went to university, understood all the intricacies of PLONK, ROFL, and Godwin's Law.
My university experience was dominated by Usenet. It was where nerds went to socialise. I bought and sold computer equipment, published terrible poetry, and learned about LGBT matters. I lurked in the
comp.lang.* hierarchy until I was confident enough to ask my Prolog questions without making it look like I was asking for help with my university assignments.
And then, one day, I just stopped.
There are three main reasons that I remember.
First was moderation. Sites like Slashdot were - at the time - pretty good at moderating out crap comments. Usenet was a stream of consciousness and, short of blocking individuals, there was no way to separate the interesting topics from the dull. Without upvoting and downvoting, it became tedious to read. And there was very little feedback on whether people found your posts useful.
Secondly was reputation. Sites like AVForums and eBay allowed you to see who was a reliable buyer and seller. Every transaction on Usenet was a risk. You might send money or goods to a scammer. Look, eBay wasn't perfect - but it made it easy to see how many successful transactions an account had made.
Thirdly was the user interface. Usenet looked dull. In a world of animated GIFs and MySpace colour schemes, Usenet didn't even have avatar images! Sure, the spartan nature meant that you could focus on a conversation - but it didn't feel as modern and exciting as the web did. NNTP software was fragile.
And so, slowly but surely, I drifted away from newsgroups into the tender embrace of web forums, Reddit, and Slack. All of them centralised (booo!) and privately owned (boooo!) but all having a nicer UI and UX (yay!)
I should briefly mention Google buying the Deja News archive, promising to revitalise Usenet, and then promptly abandoning it. Cheers Google. Choogle.
While Reddit goes through its "are we the baddies?" moment of banning all 3rd party clients and fucking over its unpaid labour force, I thought I'd return to see if Usenet was still a viable option. There was only one modern newsreader listed by my Linux distro - Pan which hasn't been updated in a year and has a GUI which gave me instant nostalgia. That's not a good thing by the way.
I couldn't find any Open Source Android apps for reading newsgroups.
And, as it happens, my ISP killed off their Usenet server a couple of years ago.
As I've said before - Slack is just IRC with a better UI. Dropbox is FTP with a better UX. WhatsApp groups are just ListServes for people who don't know how to configure a server.
Reddit was Usenet with a sparkly front-end.
User Experience matters. That's why Usenet lost. It was hard to set up, there was a ton of terminology to learn, sticky posts with group etiquette didn't exist, trolls and grieffers couldn't be moderated away, and the whole thing looked like a 1990s shareware accountancy package.
I'm a little sad that Reddit is further enclosing the commons. And I doubt this will lead to a resurgence in Usenet. But I hope it will give open source and open standards developers a little jolt towards designing user experiences which are fun and easy to use.