Americans may think of themselves as early adopters when it comes to new technology, but this chart of how fast Kenya adopted mobile money, or payments by cell phone, by World Bank blogger and economist Wolfgang Fengler , shows how big a role cultural and social needs can play. According to World Bank figures, about 80 percent of cell phone users in Kenya use mobile money. Just over four years ago, virtually nobody in Kenya was using mobile payments. By comparison, a survey by the Federal Reserve found that 42 percent of Americans don't trust mobile payments to be secure. Less than 12 percent of respondents said they'd made mobile payments in the past year.

Fengler's chart of the adoption of ICT (information and communications technology) shows how quickly the the percentage of mobile payments (in purple) followed the spread of mobile phones (in green). In 2011, the percentage of cell phone users exceeded the percentage of people over 15 years old, suggesting that most adults had mobile access. And you can see that mobile payment users now exceeds the number of people who have internet access. In other words, there are more people in Kenya that use mobile payments than there are people browsing the web on their laptops or desktop computers.

Fengler explains that mobile money in developing countries such as Kenya is practical. It empowers its people to do business without easily-stolen cash, enabling advantages like fewer lines at banks, or helping women keep money safe from thieving husbands. By comparison, countries with highly developed financial systems have monetary resources already, and mobile payment adoption requires a cultural shift.

The adoption rate has been so fast in Kenya that half of all mobile payment transactions are now from Kenya, Fengler says. Whether the U.S. catches up depends on innovations like Square, the iPhone attachment that takes credit card swipes, catching on beyond their niche appeal today.