Occasionally, I see assertions that disclosing certain private information about someone — for instance, details of their sex lives, medical history, or financial affairs — would be tortious, even if the disclosure is in a private conversation. (See, for instance, this comment, and this dissent from a Supreme Court opinion.)
But generally speaking, the disclosure of private facts tort does not apply to such private disclosures. (Of course, the disclosure might in some cases be a breach of a professional duty, such as that of a lawyer, a doctor, or a psychotherapist, or a breach of nondisclosure agreement; but those are different matters.) As the Restatement (Second) of Torts § 652D puts it (emphasis added),
The form of invasion of the right of privacy covered in this Section depends upon publicity given to the private life of the individual.... “Publicity” ... means that the matter is made public, by communicating it to the public at large, or to so many persons that the matter must be regarded as substantially certain to become one of public knowledge. The difference is not one of the means of communication, which may be oral, written or by any other means. It is one of a communication that reaches, or is sure to reach, the public.
Thus it is not an invasion of the right of privacy, within the rule stated in this Section, to communicate a fact concerning the plaintiff’s private life to a single person or even to a small group of persons. On the other hand, any publication in a newspaper or a magazine, even of small circulation, or in a handbill distributed to a large number of persons, or any broadcast over the radio, or statement made in an address to a large audience, is sufficient to give publicity within the meaning of the term as it is used in this Section. The distinction, in other words, is one between private and public communication.
1. A, a creditor, writes a letter to the employer of B, his debtor, informing him that B owes the debt and will not pay it. This is not an invasion of B’s privacy under this Section.
2. A, a creditor, posts in the window of his shop, where it is read by those passing by on the street, a statement that B owes a debt to him and has not paid it. This is an invasion of B’s privacy.
3. A, a motion picture exhibitor, wishing to advertise a picture to be exhibited, writes letters to a thousand men in which he makes unprivileged and objectionable statements concerning the private life of B, an actress. This is an invasion of B’s privacy.
In this respect, the disclosure tort differs from defamation law — a false and defamatory statement to one person (even a friend or close family member) might be slanderous or libelous. But if the statement is true but reveals private and non-newsworthy information about a person, it is not a disclosure of private facts unless it “reaches, or is sure to reach, the public.”
Naturally, especially in this era of Facebook, that line can be quite mushy; for instance, when would a post on a Facebook page that is readable by 1000 “friends” qualify as something that “reaches, or is sure to reach, the public”? (Illustration 3 — which is based on a real case — doesn’t fully dispose of this, partly because it might be influenced by the fact that the letters are about a famous person and are thus especially likely to be further publicized, and partly because the letters were sent to total strangers, rather than just to friends or “friends.”) What about a page readable by 100 “friends”? Still, it’s clear that certain communications, such as conversations or even e-mails that are unlikely to be broadly forwarded, aren’t covered by the tort.
The matter might be different in a few states, if they have a statute or a court decision that departs from the Restatement approach (which itself is based on the decisions of past cases). I know of one such exception: In Rhode Island, a statute defining the disclosure tort requires not “publicity” but “publication,” and Rhode Island courts have held that this means communication to one other person suffices to trigger the tort. It’s possible, then, that in Rhode Island it might be actionable for one friend (or family member) to tell another true things about a third’s love life, medical problems, and the like. But in most states, this would not be so.
None of this is intended to endorse the propriety of the tort, which I have criticized on First Amendment grounds; I only mean to explain what the tort actually covers.