It would be one thing if she had filmed herself in the midst of pornographic acts or if she was doing something illegal while she was naked. But just having pictures of her naked go public? Seriously, what's the big deal? Most women - and men - would kill for Johansson's body, so the fact that it is now publicly available in the nude really shouldn't matter too much. It's only embarrassing from the standpoint of some dated and puritanical viewpoints, which are hardly relevant in 2011.
Americans are still titillated with the idea that a "famous" person can be seen naked. Many mainstream films contain nudity that is much more illicit than the cell phone images that are hacked from celebrities. But it's hard to under estimate the power of the voyeuristic draw that pulls so many of us in. It's the underlying driver of the popularity of Facebook, so we have already established that it's a major social force in our connected world.
But again, if I'm Scarlett Johansson, I'm very upset that my phone was hacked and I'll go to great lengths to prevent it from happening again. I really don't care that I'm naked on the Internet.