What's your payment personality? American Express can tell you

Are you a conservative, pays-with-cash sort of consumer or a swashbuckling, smartphone-wielding early adopter? As it turns out, what's in your wallet -- and even what you consider your "wallet" -- may say more about you than you think.

If you listen to the buzz from the money and technology soothsayers, you'll hear that cash and credit cards -- not to mention checks -- will soon be endangered species. The future belongs to easy-to-use digital platforms like Square or PayPal's mobile wallet.