One indication of how deeply plastic payments have influenced the U.S. retail market has been the explosive growth in gift cards at the expense of cash, checks and other forms of plastic. Not only has the National Retail Federation reported that gift cards have effectively extended the holiday shopping season well into January when it used to end with the New Year, there are other signs as well that retailer issued gift cards have become their own commodity.

According to one CardHub.com, a website that tracks card news and helps consumers find less expensive credit cards, consumers purchased almost $28 million in gift cards over the 2011 holiday season and the site estimated that $41 billion in gift card balances have gone unredeemed since 2005.

Sensing an opportunity, CardHub has launched an exchange that it claims makes the only secondary market for gift cards among consumers who want to buy and sell them, allowing consumers to sell or swap any gift card regardless of brand or store affiliation.