Since the early days of the dot-com era, people have been buying more stuff — from pet food to diapers — on the Internet. The process was straightforward: Fire up your web browser, fill out your shipping and payment information, and receive your products in a week or two.
Then came a major headache for retailers. The smartphone, with its lack of a keyboard and a smaller screen than a personal computer, made it tougher for people to buy things quickly and easily from their handsets.
