Don't want iPhone apps sending your data to third-party servers at night? Here's what to do to block tracking and protect personal data
Geoffrey Fowler's recent investigation in the Washington Post, which showed that in just one week 1.5 GB of data was sent from his iPhone by no less than 5,400 tracking codes embedded in installed apps, is back to making people talk about the need to block data tracking by apps. Even on iPhones, not just Android smartphones.
Apple reassures users by saying it does everything it can to help them keep their data safe and provides some tools and options built into the latest iPhones to keep tracking to a minimum. Eliminating it completely is impossible, but thanks to these tools something can be done. In particular, it can be useful to enable the Ad Tracking limit and disable background refresh of apps. Finally, to protect our privacy on iPhone, it's also useful to set Safari's privacy options correctly.
Limiting Ad Tracking on iPhone
Ad tracking codes are exactly the ones discovered by Fowler on his iPhone: they are methods to uniquely (but anonymously) identify the user and record his behavior while using apps. Behavior that is then recorded in the history and used to deliver more relevant advertisements. To avoid (but it would be better to say "limit") all this you have to go to Settings > Privacy > Advertising and enable the option "Limit data collection". Apple explains that "When you turn on the Restrict Data Collection option, your ad identifier can't be used by other developers' apps to send you targeted ads." However, this system doesn't eliminate tracking altogether: while it's true that your unique, anonymous ID isn't sent, it's also true that other information is sent such as the type of iPhone you use, your phone carrier, and more.
Disable background refresh on iPhone
The background refresh feature on iPhone was created to allow users to quickly switch between apps and then return to the first app and find everything as they left it. It basically helps multitasking on iPhone, because background apps can check for updates and new content even while they're not being used. That is, they can send and receive data. And this is dangerous for the user's privacy, so we suggest you disable this feature by going to Settings > General > Update background apps and setting the toggle to Off.
Blind Safari Privacy
Another useful way, on iPhone, to browse with more privacy is to set all Safari's privacy options restrictively. Go to Settings > Safari > Privacy & Security and you'll find the settings we're talking about. Enabling "Block cross-site tracking" prevents cross-site tracking, enabling "Block all cookies" prevents all sites from tracking your behavior. If instead you want to clear cookies already on your iPhone you have to go to Settings > Safari > Clear website data and history.