"Is it copyright infringement to post a lawyer’s cease-and-desist letter?"

Sure it is but collecting damages on something that has zero commercial value to a third party would be tough.
From the Volokh Conspiracy at the Washington Post:

The University of Queensland (Australia) seems to think so; its letter to blogger Brandon Shollenberger (Izuru) states, among other things,

The University of Queensland owns the copyright in this letter and you are advised that any publication by you of this letter, or persons acting in concert with you, will constitute an infringement of The University’s copyright. The University of Queensland reserves its right to take any and all legal action against any person, including you, who publishes this letter.

Shollenberger has indeed published the letter, in the process of responding to it (see also here). Is posting cease-and-desist letters in such a situation indeed copyright infringement? I can’t speak to Australian law on this, but here is my view of American law, which I first blogged about in 2008:

A. Letters are indeed presumptively protected by copyright. Generally speaking, pretty much anything that’s at all original (not necessarily innovative, but just the author’s own writing) and longer than several words is indeed copyrighted the moment it’s written down.

B. But this presumption can be rebutted if the person copying the work shows (among other things) that his use is a “fair use” of the work. Here’s a quick run-through of the four fair use factors, and how they apply to such uses of cease-and-desist letters....MUCH MORE

Of course there is more than one way to make the existence of the cease-and-desist more widely known:


Bunch of wankers.