In the late 1980s and early 1990s, Usenet was exploding in volume, and the dominant newsreader rn (Read News), created by Larry Wall (later famous for Perl), lacked the ability to organize articles into discussion threads. Wayne Davison created trn (Threaded Read News) as a set of patches to rn that added threading at the article level and a new user interface for navigating threaded discussions.

Threading was a crucial innovation for managing the growing volume of Usenet. As Davison explained, users were shifting from a 'read most, kill few' model to 'ignore most, read few,' and a threaded newsreader allowed users to follow topics of interest without manually filtering uninteresting content. trn used article References headers to construct reply trees, displaying them as visual thread diagrams in the terminal.

trn was distributed via Usenet itself (posted to comp.sources.unix) and FTP, following the pre-web distribution model. It was based on rn 4.4 (copyrighted 1985 by Larry Wall) and maintained by Davison through the 1990s. The last significant version was trn 4.0-test77 (1995). The project is now archived on SourceForge.

trn introduced threaded discussion reading to the mainstream, a concept that would later become fundamental to web forums, email clients, and platforms like Reddit. It was one of the most important forks of the pre-web era, distributed through the very medium (Usenet) it was designed to read.