Why Mozilla? The web platform needs the capability, and currently we have to provide it in our offerings through business deals without much impact on the privacy aspects of the service. We have a unique access to Firefox on lots of devices for gathering and reporting back data. We don't have to monetize the gathered data and can make it available to the public. If we can run a successful service, we get leverage to improve the privacy aspects in the landscape.
For more information about user privacy, see [https://wiki.mozilla.org/Services/Location/Privacy "Privacy"].