> Nope, an iOS app can’t leave a cookie that other apps can use to identify me. Maybe not directly, but by using something like the Facebook SDK the same effec

> Nope, an iOS app can’t leave a cookie that other apps can use to identify me. Maybe not directly, but by using something like the Facebook SDK the same effect can be achieved by shipping your advertising identifier off to Facebook who then does the tracking server side using events generated by the Facebook SDK. This is in tons of apps and you have no way of knowing it as an end user without reading the privacy policy or reverse engineering the app. > Clearing storage is not the issue, making sure that the storage is not accidentally cleaned is. This is just as much of an issue on native apps as it is with webapps, browsers wont clear local storage for a website unless the user requests it just like how a native apps storage won't be cleared unless a user requests it. > The data consumption of an app is predictable because the download size would be listed in the appstore. On a website, it could be anything and the only way to find out is to load it. You can check out the data usage after install in iOS but there’s no easy way to do it for websites. Just because the App Store download size is predictable doesn't mean the final download size is, lots of apps download a bunch of extra assets on first launch or even regularly as you are using them. I also couldn't find a way to check data usage of apps or websites on WiFi on my iPad so that isn't really a point either way.