Obviously, when you're selling proprietary information. A service should have no right to enforce reinterpretation of the bits received any more than you have a right to enforce how people are to interpret the semantic content of your posts. (And in fact, I could easily go around selling my reinterpretation, and that only becomes a problem once you're arguing damages.)
If you sign a NDA with Coca-Cola, and they share their recipe with you via email, you're allowed to do "anything you choose" with it?
If you sign a partnership contract with Google, and they share their algorithms with you, you're allowed to do "anything you choose" with it?
Where's the line exactly of how far you can violate a contract simply because the property - intellectual and otherwise, can be represented as bits?