From the Google Maps Blog:
Last April we released a new system to help provide an address for every location in the world, called Open Location Code (OLC, also known as “plus codes”).
Today, plus codes are now searchable on Google and Google Maps.
Plus codes are a useful way of representing locations that don’t have specific street addresses. But it’s not just in less developed places like Kibera. For example, an area the size of a few beach blankets on Atlantic Beach would have the plus code 87G8H7P8+FH. If you’re hoping to tell some friends where to meet you on the beach — and they are near Atlantic Beach or looking up the specific location in Google Maps while zooming in over it — you can give them just the last four digits “P8+FH” to help them find you. You can find the plus code for your location at http://plus.codes.
Learn More About the Codes, View Examples in the Complete Blog Post