A market I had never thought about is about to get iPad friendly. A company call Square has introduced a credit card reader and app for iPhones and iPads that will allow anyone to run a credit card. As I understand it, they get a 2.5% fee, but no merchant license is required.
Think of things like flea markets, farmers markets, barbers, etc., that normally only take cash or checks. Now without the investment and fees that are needed to take credit cards, they can swipe your card when you don't have the cash. I can see a few question marks, and as someone whose wife is notorious on both sides of flea markets, I can't decide what I think yet.