Building a Business on Connection Fees

I read Ed Felten’s patient deconstruction of the economics behind the current FreeConference.com telecomm problem — in which some major carriers are refusing to terminate calls to numbers in the rural Middle West offered via freeconference.com, leading to the unavailability of what appear to consumers to be “free” conference calls — and I wonder how many other small company business models are built around arbitraging the current local exchange/long distance carrier regulatory payments structure.