Android (root): Google's App Ops on Android, which is designed to let you control permissions for individual apps, has had a strange history. It was never a consumer-facing feature and it keeps being hidden. Now a third-party app lets you access App Ops on rooted devices.
The app du jour to accomplish this is App Ops for Root. For the moment, this doesn't affect anyone on anything but the most cutting edge Android version, but as Google continues to bring App Ops back into the shadows, it grows increasingly likely that managing permissions on a per-app basis will remain a root-only affair for a good long while.