I understand your concern. All that's viewable is the city you list as your home, your username and avatar. Here is the URL for the map software to find out more information. Michel, one of the administrators probably added the map page and is the best person to ask questions about it. If you worry about your safety don't add your name there, or you could change the city you live in under "Settings" on your "MY PAGE" for added protection if you decide to put a pin on the map.
Either way I'm glad you're here. I hope you enjoy the company of the other atheists on this site as much as I do.