For instance, in a lot of Africa mobile operators have filled in for the role of credit cards and things like that. People pay for everything via sms.
Clean drinking water was available from wells.
But if you google for pay by sms, you'll see there are A LOT of services for that.
Also here's an article with some statistics: http://www.pewglobal.org/2014/02/13/emerging-nations-embrace...
In Kenya, for instance, 68% of phone users make/receive payments on their phone. And 76% of them use their phones for social networking. At the same time, 82% of Kenyans have a mobile phone. But only 59% have access to clean water. -> http://water.org/country/kenya/
So that's .82*.76 = 62% of Kenyans with social networking vs. only 59% with clean water.
I'm surprised it didn't catch on sooner. It's a genius idea for enabling online payments in places where credit cards, PayPal etc. aren't as commonplace as they could be.
At the time, 93% of South Africans had access to clean water and mobile penetration was at over 100%.
For the whole of Africa, it was ~46% water to 50% phones.
But, as ever, definitions are important. If you have to spend half a day walking to a well for a bucket of water - that counts as access. Similarly, a family who shares a phone each has "access".
It's also a lot easier to build a mobile phone network than a water network. Stick up a tower, power it with a generator / solar power, and point it to a back-haul link. Hey presto, you've got wide area coverage.