I understand that there are ethical and possibly halachic issues with publishing a letter or piece of email that I receive from another person without explicit permission. What are the considerations in handling a letter or piece of email from an agent of a corporation (acting officially)?
If I receive a bill that seems outlandish, like a $100,000 phone bill for 20 local calls, may I post a scan of it to my blog?
If I have written to a corporation for information on some subject and they send a reply containing that information, may I share it? (For example, the email I received from the OU that I mentioned in this answer about a hechsher.)
If I have sent a letter of complaint and published my own letter, may I publish the reply I receive? Only if they helped me? Even if they declined?
Does a corporation, or someone writing on behalf of one, have the same expectation of privacy that a "regular person" would?
Of course CYLR and CYLL (lawyer) for practical advice, but I am looking for information that would inform that discussion, whether halachic or from mussar.