If you find an interesting local business in Google Maps, you can add it to a custom map for future reference. The process has been simplified and Google Maps added the option to bookmark search results. You'll find stars next to local search results, locations, user-created maps:
To find the list of bookmarks, click on "My Maps" and scroll to "Starred items". For now, the bookmarks aren't public and you won't find them in a user's profile.
The starred items are also added to Google Bookmarks, without any label or annotation. If you remove the pages from Google Bookmarks, the corresponding items from Google Maps are deleted.
{ Thanks, Imma. }