@msbernst @axz @karger I still use trn today, and find its interface unsurpassed. Gnus implemented threading with multiple backends, so it could thread email archives as well as netnews, and a lot of people (by 1990s standards) used it as a mail client, well before other email programs implemented threading (mostly badly), although a lot of the communication we used to use email for has moved elsewhere so correct email threading is less necessary than it used to be.