Basically it is a simplified alternative to using coordinates to share precise locations. You type in 3 words separated by dots such as, "assure.races.translated" and you can find a specific 3x3 meter space in the entire world! These 3 words directed me to the top of lake at the Cobb Estate gate.
To use this you click or tap on a square overlay like shown in the picture and each square will have its own designated 3 word code.
Below are some other examples.
