Most of the time these were either misunderstandings, or wilfully misleading scare stories: These services need some sort of license to work. Even just to show

Most of the time these were either misunderstandings, or wilfully misleading scare stories: These services need some sort of license to work. Even just to show you your own photos, you need to give Google/Facebook/Apple/whoever a license. That license was usually quite liberal, i. e. "a non-exclusive, royalty-free perpetual license to perform your works...". That scared people, and suddenly everyone thought Facebook owns all you photos. But the [...] usually contained the conditions, or the reasoning. So, for example, they had the "perpetual" license to those works because it would have been difficult to securely eras everything from every backup. But you still had/have the right to stop their showing of your photos. And they certainly never had the right to "perform" your works in the way that copyright is usually turned into money. They cannot, for example, sell your photos. Google never owned all the copyright in Harry Potter, even if the manuscripts were all sent via Gmail. Otherwise I'm pretty sure we'd have heard about it (It wouldn't be enforceable in court anyway, no more than some ToS clause transferring your house and firstborn). What they can do is data mining. So Google can show you ads that match your inbox, and Facebook can train object recognition on your photos. But I'm not even sure if they need a license for that–it's just reading, not performing. They probably only need your consent for privacy reasons.