Apple's iOS has a lot of great security and user privacy protection capabilities -- more than any other competing mobile platform. But it also has flaws that undermine some of those very capabilities. Here are three you should know about, along with my advice on how to take care of them.
1. Getting to the hidden privacy controls
First off is privacy. Apple has long had privacy controls in iOS (and more recently in OS X) that let you decide which apps can access personal information such as your location, contacts, and photos. iOS 6 has expanded those controls to include permissions over which apps can use your Bluetooth radio to share information with other devices. Apple's privacy controls are great in that apps must ask you for permissions, and if you grant them permission, you can always revoke it on a per-app basis at any time.
You manage the privacy in the Privacy pane of the Settings app, which gives you one location for these controls -- except for two items.
The Safari browser has a private browsing mode that stores neither cookies nor a URL trail, so your Internet steps can't be traced. This control resides not in the Privacy pane but in the Safari pane; just set the Private Browsing switch to On. (You can tell private browsing is enabled because the Safari background changes from light gray to dark gray.) In OS X and Windows, private browsing is an application preference, so it makes sense that in iOS the private browsing control resides with Safari's settings, not overall privacy settings.
But it doesn't make sense that Apple has hidden the ad-tracking off switch in the Settings app's About pane -- buried below a bunch of information entries that seem clearly designed to hide this feature from users. Bad Apple! If you want to limit what information in-app ads can track about you, set the Limit Ad Tracking switch to On. To get to that switch, go to the General pane in the Settings app, then tap About. Scroll to the bottom of the About pane and tap Advertising. Only then is the Limit Ad Tracking control visible.
Hidden in the About pane in the Settings app's General pane is the control to limit ad tracking.
While you're at it, head over to your carrier's website and check your account settings to make sure ad tracking and other forms of tracking are turned off -- the carriers track you, too. Here are the instructions for Verizon Wireless; I suspect there is a similar process at every carrier's website, but if you can't find them, call customer support and make them spend money on supporting your right to be left in peace.