There are many questions on stackoverflow where a response will (accidentally or deliberately) link to pirated books. This is usually detected and corrected in short order. However, the edit history dutifully preserves the links to the pirated material for all to see (and click). Indeed, a google search for
site:stackoverflow.com pirated books will bring up many offenders.
Is this a problem? Is stackoverflow still responsible for linking to the pirated materials, even though the link only appears in an edit history? Is there a process to expunge such links more thoroughly?