Achievement systems are a major part of gamification for a big reason - they help the user/player/learner chart his or her progress through their journey with concrete milestones tailored to their personal experiences. They're critical...and wickedly difficult to construct. Some thoughts on the X-Box's system and problems it experienced.
Are you a gamer AND a data nerd? Join the club! Here's a great study of the chess board and the survivability of chess pieces on that board. I've never looked at the game quite this way before.
Anyone out there playing Elite: Dangerous and using its play engines to create gamified experiences? I understand that this wildly huge open sandbox is bigger than anything in our past experience as players, but don't know how difficult it is just yet. Still, I'm looking forward to playing it and learning from it.