No Cash? No Problem!
In the past we've gone from trading goods to trading coins, then from coins to cash, now we trade with nothing but electrons. Digital credit has changed the way the world does business. While there are some downfalls with digital transactions, I'm only discussing the next 2-5 years of digital transactions on a personal level.
While the coin was actually invented back in about 660BC and widely used in the Persian empire, the Greeks and Romans used it as a widespread method of trade. Archimedes determined the coin's value could be set based on the physical coin itself. The weight would stay constant, and even if the coin had been tampered with the coin was still made of some sort of metal. This allowed the Greeks to cut down on counterfeited coins. But today we have similar issues with credit cards, we need to ensure that the credit cards are not stolen or fake.
The future is companies like Squareup.com a product for your iPhone in which you can take credit card payments anywhere you have cell service.