1. That is not true because even if every bit of information is made inherently public it does not mean that the information is not prone to manipulation.

2. Well, there should be laws that enforce that the privacy stuff is included in every product. Windows and walls will work with noise cancelling and act as a Faraday cage. Windows will also need to have mirrors on the outside.

3. That's why I wrote 'wider' in parens. Of course one would be able to widen the privacy sphere, i.e. you'll still be able to join gatherings in a completely natural way.

4. Again, I didn't say that you shouldn't be able to reveal yourself. If you want to share all your relevant thoughts and actions with your coworkers you are free to do so. I think with a slick user interface (e.g. a brain implant) and various automatic/self-adapting filters that could work quite unobtrusively, so I don't think your usability objections are particulary strong arguments.