For my copy of "The incredible machine" I had a copy protection challenge page in the manual, the game gave you a challenge phrase and you had to enter the proper password. I think different game versions also existed for which you needed a different manual. Goal was to make it harder to just copy the floppy disks, you also had to remember to copy and print the paper, which was an additional hurdle.
Later, I also had lots of burned CDs from friends with games on them.
I'd say the piracy was mostly real life friends sharing their games with each other (which, since everyone knows different people, was quite a big network), which yes, still made it common and quite a problem for publishers.


