Anonymous FTP
The convention of logging in to an FTP server as anonymous with your email address as the password — open downloads before the web.
FTP requires a login, so archives that wanted to share files with the world created an account anyone could use. Etiquette said the password should be your email address, so the admin at least knew who was downloading; in practice plenty of people typed guest or nothing at all. Files lived under /pub, and /incoming took uploads. RFC 1635 wrote the custom down only in 1994, long after it was established.
University archives such as wuarchive and ftp.funet.fi, where Linux was first posted in 1991, were the internet's software library. Archie existed to find things in them. HTTP took over distribution, and browsers dropped FTP support around 2021.