By Donald Ritchie
In my article, Getting started with My Places in Google Maps, the description of the privacy and sharing options was a little misleading.
These options appear in the left-hand panel while you are editing the map. They allow you to make your map either "public" or "unlisted". I said (correctly) that the options don't affect how you share the map. Regardless of the setting, anyone who knows the map's URL will be able to see it.
I also said that choosing "public" allows the map to appear in Google's search results. That's not quite right
In fact, My Places maps never show up in a map search. If you search within Google maps for your map's title, you might find places on the map that are related to the title, but you won't find the map itself. But the map might show up in Google's general search results, just like any other web page.
The privacy setting doesn't affect any of that. In fact, just about the only thing that the setting affects is the visibility of the map in your Google Maps profile (visitors reach your profile by clicking on your user name in the left-hand panel).
So, if you don't want visitors to see the map when viewing your profile, choose the "hidden" option, otherwise choose "public". If you don't care either way, just ignore the setting.