In The Princess Bride by William Goldman, there is an extended section where the author says that he wanted to include a reunion scene when Buttercup first discovers that the "man in black" is in fact her beloved Westley, but his editor didn't want it in. So as a compromise, Goldman tells you to write to his publisher, Houghton Mifflin Harcourt, and they will send you the "missing scene".
Unfortunately, the company no longer exists at the address given. My eBook copy also includes an asterisk after the address that, when followed to the last page, says this:
*I've been writing since Eisenhower's been president and I think this is my first asterisk. I feel giddy. The purpose of this is to announce that time has marched on. If you don't want to wait to read the reunion scene, you no longer have to. Just go to the Internet and log on to www.hmhco.com/princessbride. You'll see it right on your very own computer screen.
As it turns out, that URL goes to a dead link, and Archive.org's only history is an error page.
So what was the "reunion scene" that you would get if you wrote to the publisher or visited the website? Was it actually an additional narrative, or was it just an additional joke, such as claiming that the manuscript was lost as the book went to print?