I just bought usenapp (https://www.usenapp.com/) after using Unison for ages on mac. This is a useful backbone map of the usenet networks: https://upload.wikimedia.org/wikipedia/commons/7/7d/Usenet_P...

I have a hefty block account that's my primary server, and then a TB of block data from other backbones set to be only used when my primary server is missing data.