Interesting article, and discussion, thank you all. Many relevant points. However, one thing I think hasn’t been mentioned is “The Magical Number Seven, Plus or Minus two” by George A Miller. Wikipedia has a good synopsis. TL;DR – short term memory capacity is better measured in ‘chunks’ rather than bits.

This is where using 3 words would be a benefit – for native language speakers, that should only be 3 chunks.

Example:
///care.reef.sank
… is much easier to remember than a decimal lat/long …
51.506750, -0.082342
… and if you use arcminutes and arcseconds …
51° 30′ 24.3” N 0° 4′ 56.4312” W

That last example is maybe 8(?) chunks. And there is no UK Postcode for that location.

Oh, and I’d not heard of Plus Codes – but that would be:
9C3XGW49+P3
Yes, I’m including the Area code, and for that location it isn’t necessary. Still not sure that’s easy. Interestingly, without the Area code, it is 7 digits long.

I know that we would just use a 20 digit number and be able to locate somewhere to the nearest angstrom (or whatever 🙂 ), but for a lot of people, that’s too hard. Try watching your 80-something year old granny read a credit-card number over the phone (if she’s like mine, bring a book). Now make that your target audience.

All the comments about proprietary tech are entirely valid, and would make me uncomfortable about using it. But then I don’t like UK Postcodes either (try getting a database of all of them, including Northern Ireland). Lat/Longs are surprisingly difficult for people to use, country’s grid systems tend to be country specific – seems like there are always compromises. In this instance, What3Words does at least have the benefit that most people can handle 3 words.

Anyway, a very interesting discussion 🙂