Rating Systems attempt to assign a numeric measure to a player's strength based upon the player's results in games against other players. There are a number of rating systems in use across the globe. Some ratings systems are limited to particular countries or organizations others span either a continent or the entire globe via Internet play.
- French Ladder which is essentially GoR with parameters retuned
- Glicko Rating
- GoR used by the European Go Federation (EGF)
- Korean Professional
- Sonas by Jeff Sonas? of ChessMetrics
- TruSkill: A Bayesian skill rating system
- Whole History Rating a modern rating system claiming to have the highest accuracy for rating players whose playing strength changes over time.
- Russian (text in Russian)
- EGF Rating per Rank
- FIDE titles and EGF Go ratings
- Holigor's Rating Of Go Players
- Point Ranking Scheme at Tokyo Go Clubs
- simple point ranking scheme
- Migeru's musings on go ratings
- Internet Ratings Database
- How to align rating systems
- Rating Theory Homepage
 http://kashi.dip.jp/~kashi/rating/rating.pdf seems to comprise interesting content w.r.t. ELO (I guess, tderz). As it is written in Japanese (which I cannot read beyond some Igo-terminology) s.o. else might comment more on it.
Some figures resemble derivative pricing model graphs near expiration, where volatility goes up and normal Black & Scholes do not hold anymore.
With Go that would be slightly different: near same strengths encounters give very predictable results,
high strength difference encounters bear high uncertainty/volatility/deviation.