The way I remember it, in the US there are rural telcos that can't afford to maintain infrastructure out the revenue they pull on sparse populations, but the go

The way I remember it, in the US there are rural telcos that can't afford to maintain infrastructure out the revenue they pull on sparse populations, but the government believes it's critical that citizens have telephone access anyway. So when a call is placed inbound to telcos of a certain class (size, revenue, I'm not sure), the destination telco receives a fee / subsidy (I think from the telco originating the call). People figured out that they could run free conference call services hosted on rural telco phone numbers, bringing in oodles of calls, then collect a cut of the subsidy.