I disagree. Moderation plus meta-moderation would work well for the singular task under discussion: putting shredded documents back together. And because there'

I disagree. Moderation plus meta-moderation would work well for the singular task under discussion: putting shredded documents back together. And because there's no usernames or discussion involved (displaying "User happykitten92 made this move. Was it correct?" would defeat the purpose of preventing troll collusion), everything is done anonymously so nobody has a fiefdom they are protecting; the value is in accomplishing the goal. To add to this, the concept is not exactly new when it comes to crowdsourcing. Casting Words uses these approaches with Amazon Mechanical Turk for validating others audio transcription for accuracy, formatting, and so on.