The forum I used to frequent and which ultimately led me here was a place to complain about one's inlaws. Mostly, daughters-in-law complaining about their mothers-in-law. That place was absolytely RABID about never posting material from other websites, the logic being that their own posters may, in a moment of angst, post delicate revealing information that they might later want removed, and if it were carried off to another locale, could not be. So they were extending their "protection" to other sites as a matter of course.
I'm sure maybe once, some gal really did post personal information about a truly homicidal mother-in-law who found her out. Maybe once. But for the most part, they were just a bunch of bitchy, catty, ungrateful control freaks who would complain about anything and everything (and most probably had DU names). I believe that if you put it out there, you should be responsible for it.
And swift removal of a posting doesn't always thwart the google cache.