[joe_the_user]

If someone seriously wants to only share their P!=NP proof privately, they need to put "not for wide circulation" as a watermark on every page.

But who know what the authors thinking was? Perhaps he hoped they'd share the paper only if they were sure it was right, perhaps he expected they wouldn't share it at all. Perhaps he expected they'd share it and he was already convinced the paper was correct. Perhaps he didn't care to what people outside the field thought...

[mzl]

If I get a paper with request for comments in a personal mail from an author, I would definitely ask permission before forwarding. Not doing so is just rude.