An example, there use to be this guy names Fred Fish who would compile Amiga freeware onto floppies and trade them at Amiga user group meetings. I believe he lived in Idaho. Where he got the freeware was anybody's guess. But through a thin network of people trading software, the Fish disks (as they became known) spread far and wide. I didn't have an Amiga, but one of my friends did, and he had probably 30 Fish disks, which composed most of the library of software he used (there were about 1000 of these disks).
Generally, they weren't transmitted by BBS, nobody had internet. These were literally n-th generation copies of the original disks Fred Fish first put together on his computer and gave out at his local group and to his friends. People from around the world ended up with Fish disks, which are usually reverently numbered according to the release packages that Fred put together.
People used to organize "copy parties" where we'd all haul our huge computers, tower-CRT monitor, sometimes speakers, over to somebody's house and we'd spend all night copying floppies and sharing software and .mod files and whatever else. Showing off games and drinking and smoking and doing all other kinds of crazy things. Fish disks were common sights at these parties and everybody wanted to fill out their collection or get the latest one...which may have percolated thousands of miles and over oceans -- by hand to get to this party.
The movie "Hackers" is a terrible movie from a technical standpoint, but it really nails the feel of this culture. Competitive and cooperative, doing something a little bit wrong, mostly at night. Viruses in those days were designed to spread in this kind of environment of social sharing, embedding themselves in weird spots on floppy disks and taking up just hundreds of bytes.
Modems started to kill lots of it off, and widespread Internet killed off the rest. But it was an amazing time.