After the Instagram debacle, where it changed its terms of service to give itself greater rights over user photos and reversed itself after a user backlash, it's worth thinking about the security threat stemming from terms of service in general.
As cloud computing becomes the norm, as Internet security becomes more feudal, these terms of service agreements define what our service providers can do, both with the data we post and with the information they gather about how we use their service. The agreements are very one-sided -- most of the time, we're not even paying customers of these providers -- and can change without warning. And, of course, none of us ever read them.