Hybrid online/offline transactions
Patrick McKenzie's fantastic breakdown of how online transactions work in a society where not everyone has access to online payments.
Patrick McKenzie's (@patio11) recent post about how online transactions work in Japan, where relatively fewer people have methods of online payment (e.g. credit cards) is a fascinating and nostalgic read for me. The tl;dr is that the convenience store (aka konbini) has over time become the locus of remote transaction: ubiquitous, powerful, and highly automated, it connects to merchants to process payments in cash via a integrated set of networks that overlie (but are accessible from) the konbini.
Japan actually takes it a step further than online payments by providing a number of physical certificates that can help merchants (and, well, anyone else) verify your identity. I had to use a Residence Certificate (juminhyo) when I bought my Subaru, for example—because just showing my driving license wouldn't be secure enough to prove who I am. (This makes sense: some people don't have driving licenses; some hotels to whom I provided my driving license probably employed less-than-Fort-Knox-worthy levels of digital security.) I took a trip to Yubetsu's Town Hall for this, but it sounds like nowadays you can get it printed remotely—at your local konbini.
I've long lamented the fact that the konbini doesn't seem to exist in western countries, despite being such a critical piece of social infrastructure in Japan. What I wouldn't give for a late-night meander through the dazzling white aisles of a 7-11 these days, the sound of muzak Daydream Believer overhead.