But fair use includes things like criticism and parody - the main reasons why I might want to publish an email I received from somebody. Also, if someone tries

But fair use includes things like criticism and parody - the main reasons why I might want to publish an email I received from somebody. Also, if someone tries to sue me for damages for publishing their copyrighted email, they're going to have a hard time convincing a jury that they suffered any losses: Why would an email they sent to me have commercial value as a publishable work? (That makes it different from a book.) And they're going to have a hard time convincing a judge not to throw out the lawsuit, since the lack of potential damages makes it clear that the lawsuit is simply being used to harass me. There may be things that somebody sent me, such as confidential business information or confidential personal information that I probably shouldn't publish. If I published something like that, however, they probably would sue me for damages based on something other than their copyright of the words they sent me (e.g., invasion of privacy[1]). But if someone just sent me an email raving at me for something I said on the web, I see no legal obstacle to publishing that to criticize it. Of course, when in doubt, consult a lawyer (which I'm not). [1] https://legaldictionary.net/invasion-of-privacy/ https://legaldictionary.net/invasion-of-privacy/