Ask and you shall not receive
The Washington Post recently ran a test on data flows from some popular iPhone apps. Even the ones that were not tracking you, in fact, were. Well, technically it wasn’t tracking, but “fingerprinting” – the process of obtaining enough infomrtion about your device that a the device (and presumable operator) could be easily identified. Although this is usually used by law enforcement against criminals,the techniques being used more and more against websites visitors.
On your iPhone, you can now tap a button that says, “Ask app not to track.” But behind the scenes, some apps keep snooping anyway.
You can find their investigation here.