In the early bitcoin years, proponents promised that you would soon be able to pay for anything and everything with cryptocurrency. Order pizza! Buy Etsy trinkets! Use a bitcoin ATM! While PayPal had existed for more than a decade, frictionless, social payment platforms like Venmo were just first taking off, and cryptocurrency seemed like a legitimate way for digital transactions to evolve. It didn't happen.

Get in-depth coverage of current and future trends in technology, and how they are shaping business, entertainment, communications, science, politics, and society.