Charges fly over shops' credit-card feesCNNMoney.com - USA

The public debate continues over government regulation of the card payment networks built by MasterCard and Visa. 

With more than a million new merchants signing up to accept payment cards in the past year, it is argued that the network effect balance of setting Interchange high enough to provide the banks an incentive to issue the cards, but not so high that merchants won't accept them, is working. 

A major factor behind retailers' objections is that as consumers use credit and debit cards more frequently and that the fees have also increased as the card companies have upgraded more consumers to rewards cards, which carry higher fees.