Until a few weeks ago I've never heard before of 3words, but they seems to be online from a very long time.

Another similar geo location system, if I'm not wrong created by Google but released with a liberal license (Apache) and not patent encumbered, is called "plus.codes".

Edit: according to Wikipedia they were founded in 2013, don't recall why I thought they were older...

That's nice to learn about this alternative.

I haven't worked a lot with geolocation yet. But I'm driven to it because of my geography background, and I would be mad if every service for that kind of work was closed and proprietary.

It has to be an add, if they could download the app they surely could've sent their location to someone