One of the differences between Android and iOS is that Google Play presents detailed information about the permissions requested by an app (eg, access to the contacts list, GPS location), whereas the iTunes Store doesn't.

Security vendor Bitdefender has moved to redress that with Clueful, a web app that describes potential privacy violations by iOS apps.

For example, it shows that the official Facebook app can read your Address Book, could track your location, connects to Facebook (well, yes...) and encrypts stored data.

Other characteristics noted include warnings of apps that access calendars, drain a device's battery, overly target users with ads, or track and aggregate the owner’s usage through multiple analytics networks.

Another example is that the free version of Angry Birds tracks usage via Flurry, can display advertisements, and could track your location.

Why would a game need that last capability? Probably to display 'relevant' ads.

The new version of Clueful provides for comments from users.

It has been released as a web app as Apple pulled the native app version from the iTunes Store.

"The iPhone is the most personal of your personal devices, storing large amounts of private information that app developers would love to access. We feel Clueful is one of the most useful and valuable tools available to consumers and are excited to relaunch it," said Bitdefender's chief security researcher, Catalin Cosoi.

"We're putting Clueful out as a comprehensive, full-featured guide to iOS apps with added social features and are preparing further advances for this new technology."