bit.*
The Usenet hierarchy that mirrored BITNET mailing lists, letting two academic networks read the same discussions.
Around 1990 BITNET and Usenet were parallel universes. On BITNET, discussion happened on LISTSERV mailing lists that arrived in your inbox; on Usenet it lived in newsgroups you went and read. The bit. hierarchy bridged them: gateways took traffic from popular lists, posted it as newsgroups — mostly under bit.listserv. — and sent replies back to the list.
It sat outside the Big 8, had its own administrators, and plenty of news servers carried only part of it. Some groups outlived both parent networks; bit.listserv.ibm-main, about IBM mainframes, was still busy long after the last BITNET node went dark.