Most of us use a credit card now and then when buying goods or services from a merchant.
But what about a consumer-to-consumer transaction? I'm guessing that most of us have yet to purchase or lease a credit card reader, prompting payment by cash, check, PayPal (if available), etc.
The current issue of Fortune magazine has an article on Jack Dorsey (of Twitter fame), who has developed a small rectangular card swiper that will plug into the audio jack of a mobile device. You'll find the article here, with additional reading here and here, and a video story here.
I think the world is passing me by. Thank goodness I have young, tech-savvy, children who can help me survive.