I thought that Usenet newsgroups died out 20 years ago - but apparently not. These (mainly text) groups, distributing conversations over 'nntp' servers, are still around, albeit not carried for free by ISPs - these days they're hosted by commercial servers and you have to pay to get access. To the point, NewsgroupsRT is a newish UWP application for Windows 10 (including Mobile) that provides a sophisticated themed interface to the groups and their messages.
NewsgroupsRT is a usenet newsgroup tool to read and post articles on NNTP servers with and without authentication. NewsgroupsRT is designed for text und not for binary newsgroups.
Read and post articles
Tile, badge and toast notifications
Hierarchical representation of threads
Support for Windows 10 devices with different screen sizes
Extended information about article state (new / read)
Offline functionality (Read already downloaded articles without an internet connection)
Attachment download and upload support
On Windows 10 Mobile, on my Lumia 950 XL:
Setting up a Usenet server configuration - this is the free Mozilla test server, by the way; (right) This is a very sophisticated app, and there's plenty to fiddle with, which is just as well, given the varied nature of Usenet groups and content!
Looking at groups on the server, and then (right) at individual messages, along with context sensitive actions.
And on Windows 10 on the desktop or in Continuum from the phone:
Do note again that 'binary' messages (text-encoded images, videos, music, and EXE apps) aren't supported. But then there are plenty of other ways to access and share multimedia these days. This is 2021!