Very informative, it's interesting because I never realized how much TrueSkill uses relevant probability rules. I'm in a college level statistics class and it's cool how we've learned about the Normal curve with mean (Mu) and Standard deviation (Sigma), and how it relates to this system. If only only the Mu and Sigma values were known of everyone in every game you played...I'm sure the ranking system would be much more predictable. Great Job!