[joezydeco]

In the early days in the US every call was billed. If your call was to another city or even area code then it was a "toll" call and was even more expensive. That sparked the traffic in stolen calling card codes (an account with a long-distance telephone company). Most of these "codes" were only 4 digits so many people wrote programs to brute-force the codes. Then they were traded rapidly to spread the blame and, again, were treated as currency.

Later on some phone companies offered "call-paks" which allowed unlimited calls to numbers in the same area code. But that still didn't cover long-distance. FIDOnet was a clever way to let you call locally and still work nationally.

Operation Sundevil took down a lot of the hubs for trafficking LD codes, but by that time a lot of BBSes were turning into internet ISPs and modeming over long distances wasn't necessary. Things faded off after that.