Customer Loyalty Programs

HBS Working Knowledge on Customer Loyalty Programs that Work. " ... The customer rewards cards that clutter wallets and clog key chains of many a shopper may soon be no more, as retailers move from physical to digital (read: mobile apps) forms of loyalty program member identification. It's a smart decision. Unfortunately, it's one of the only smart decisions retailers are making when it comes to customer loyalty schemes.... ".  Some excellent examples of companies that do it well.