The pioneers are first, and they get the arrows in their backs. Some companies move early, and then the herd tends to move all at once. Similarly, the ones that move late may find that they're not relevant anymore. One of the deep issues about edges is that they are not trouble-free. Corporate e-mail policy is one.
Some companies save e-mail, and they claim the right to access all of it.
They don't want to be embarrassed by it. There is a flip side. That's a case where Microsoft probably wished it could have lost its e-mail. Another aspect of the issue is employees who are concerned about their e-mail being monitored and are afraid the company wants to keep and watch everything they do. My sense is that we're going to shift the balance.