Interestingly, the problem is caused by Facebook trying to fix the problem. The hypothesized reason the clickfarms "like" random pages is to seem real because Facebook will shut them down if they don't seem real. Perhaps Facebook could drop that specific ("has the user liked other pages?") signal from their bot detection and focus on other signals. Whatever they do will likely result in some type of side-effect as clickfarms continue to strive to "seem real".
