We'd like to know too. Is there any lawyer here to help us understand
Transparency vs Confidentiality

I asked our lawyer in front of the entire board at one of our meetings. The 1st amendment is alive and well, including being able to tell shareholders what is going on in their building. Naturally anything of a personal nature is excluded, such as quoting someone's income tax returns from a Board Package for a purchase.
Politics does dictate that you try hard to maintain good relations with the rest of the Board in order that you all do what is best for the building. Creating hard feelings is never advised, unless you have a very good reason. Judgement is the byword here!

I know a board member that was informed by the President of their board that because a shareholder was helping them on a small project (getting money back for the co-op from a vendor) that this board member should be removed from the Board for giving out information. The President of the Board actually contacted the co-op attorney and included him in the email. I also don't think the majority of the board members even wanted to do that. It didn't get that far but of course the Board member was upset. Also the President of the Board wasn't on top of getting the money and because of the shareholder they were able to get back over 50K. Also this information was also discussed to the shareholders at a group meeting in the building lobby but no one was on top of it so how confidential could that be?

Our coop's by-laws contain this section. I think this is pretty common:

Section 12. Confidentiality: Information disclosed to directors should be kept in confidence and not disclosed under any circumstance until a decision is made by the Board to make the information public. Once determined, decisions of the Board are to be presented in their final form, and any discussions leading up to such decisions are confidential. Board members shall never disclose how other Board members voted.

There's no bar to disclosing how *you* voted, though you should use common sense and good judgment in disclosing such information. Also, our board typically publicizes the rationale behind significant decisions, especially if they are likely to lead to questions: "Why did you raise maintenance?" or "Why is such-and-such prohibited?"