Not to panic you or anything, but pretty much the driving purpose of iOS apps, especially free apps, is to collect information about you in order to sell you ads. You know those “permissions” that you never read for apps? That’s just the stuff they have to tell you about.
Clueful
So, figure out what’s what with Clueful, a webapp that tells you what your iOS apps are doing.
Clueful may sound familiar, as it used to be an iOS app. But for some weird, obscure reason, Apple had an objection to an app that outed some of the crappier practices of the programs it collects a cut of, so Clueful has migrated to the web.
For example, if you run popular social traffic app Waze through it, you’ll find that Waze connects to social media, stores data using encryption, and so on. It may not sound like much, but it’s worth running any app you’re considering adding to your phone through Clueful. That way, your privacy is protected and you don’t have to worry about that crappy Christmas app tracking you.
Clueful [Official Site]