Every open source project is centered on a community. This section provides you with many useful links to the project's page and forums, as well as a number of helpful articles, tutorials, blogs, discussion groups, and social media forums (Twitter, Google Plus, Facebook) for Google Map Maker contributors. You can, however, navigate your way to the majority of all these forums and resources form the central Map Your World Community from here: http://goo.gl/imKJ2.
You can take a look at Google's official Map Maker discussion forums (http://goo.gl/Wc9Zh) and choose which forums and communities to join based on your interests. Here, you can post and share your experiences with fellow mappers across the world or within your region. The forum allows you to subscribe to discussions involving Map Maker and also have hearty exchanges and collaboration with fellow mappers around the world. Important updates and changes to Map Maker are communicated to the community through these forums as well.
Take a look at the official guideline (http://goo.gl/KbSdF) for reviewing and moderating edits in Google Map Maker if you are in doubt or unsure of what and/or how to go about it.
If your find yourself stuck or want to make reference on how to carry out some operation in Google Map Maker, this is the official repository and reference point for any of that (http://goo.gl/yP8oG).
If you want to stay informed with all the latest updates and changes to all of Google's Geo platforms including Google Map Maker, this blog (http://google-latlong.blogspot.com/) is the one you need to subscribe to and bookmark. Don't worry, it's not spam.
Follow Google Map Maker on Twitter at https://twitter.com/googlemapmaker, on Facebook at https://www.facebook.com/GoogleMapMaker, and on Google Plus at https://plus.google.com/+GoogleMaps/posts to stay updated with all the latest happenings in the world of maps and Map Maker. You can also watch all your favorite video tutorials about Map Maker on YouTube. Subscribe and follow the Map Maker Channel at http://www.youtube.com/googlemapmaker.
Would you like to make a formal request to Google to download some of the data in Google Map Maker for non-commercial use? Put up your request (using this link: https://services.google.com/fb/forms/mapmakerdatadownload/) and explain why, who, and how you would like to use the data and Google will get back to and after ascertaining all the above, will avail to you the data for download in KML format. Read more on GIS data formats, here, at http://en.wikipedia.org/wiki/GIS_file_formats.
Catch all the edits live in real time as they happen in Google Map Maker from here (http://www.google.com/mapmaker/pulse). This is my personal toy in Google Map Maker as it shows me the edits live as they happen and who is making them across the globe. The tool auto-pans across the regions as the edits keep coming through. Try it!
I wish you all the best in your mapping endeavors.