The kind of security Linux does is binary and has correct answers: should this user be logged in? Can this user write this file? Should this [more complicated a

The kind of security Linux does is binary and has correct answers: should this user be logged in? Can this user write this file? Should this [more complicated access using SELinux] be allowed? Search rankings are relative to each other and do not have objectively correct answers. Furthermore, I think the methods people have discovered so far to produce search results users are happy with are all gameable to some degree, so the only option available at this point is a degree of security through obscurity and an ever-evolving arms race between Google and spammers.