“We estimate that M‐PESA had reached nearly 40 percent of the adult population after a little more than 2 years of operation, and that now, approaching only the fourth anniversary of its launch, is used by more than two‐thirds of households.” 

How beer paved the way for civilization. Yes, beer.

Eva-Lotte Lamm's great notes of a presentation by David McCandless and Michael Blastland.