The Paper Circuits
Fanfiction, and thus Pros slash fanfiction, which was some of the earliest slash
fanfic, began as stories written by friends for friends, eventually expanding
into "official" "paper circuits", although there is presumably
still a great deal of writing that remains private and will probably never be
seen online.
There were two original circuits, one based in the UK and one in the USA. The
latter has been defunct for a number of years, the collection mostly split up
and sold to private buyers.
More information about the history of the Paper Circuits would be very much appreciated!