Google renamed and overhauled their City Experts program, which you can participate if you write reviews on Google Maps. The new name is now Local Guides which is a better name in my opinion as before and the program got an update as well.
Google introduced now a level system and there are currently 4 Levels. Each level brings different benefits for you, just check them out here. Finally there will be also a Badge for Local Guides participants, which will roll out in the next couple days. First on Android and later on iOS.