Google Map Maker was introduced back in 2008, as a way for users to make contributions to Google Maps. Features like roads, highways, rivers, and so on could be added to Maps, and users could fill in details about businesses and other specific locations. After some vandalism occurred thanks to Google's poor moderation, the feature was removed entirely, and re-appeared later with less functionality.
Google has been working to integrate Map Maker features into Google Maps itself, and announced in November that the independent Map Maker service would shut down. Now Map Maker is officially dead. Google's support page says that most of Map Maker's functionality is already in Maps, and the company will continue to add new features as time goes on.
- Google Support