Word of the Day: Conference Call

OK, this is a weird one. Why do you see so many ads for free conference calls? I read somewhere that it's a function of telephone exchange. Something like long distance carriers have to pay local exchanges some kind of fee to do the hookup, particularly in rural areas. That's why there free conference call services always have some area code you've never heard of. Whatever this system of subsidy is, it seems outmoded, but I guess someone is making money off of it Free conference call.