elorating system used by mark zuckerberg given by eduador for facemash

The algorithm is actually a simple and common one, called the Elo rating system, which is used to rank chess players. In The Social Network film it is presented as something complicated and amazing, but it has been used for years in official chess rankings. In the movie Mark Zuckerberg asks his friend and soon co founder of Facebook to give him the algorithm so he can use it on Facemash to rate girls who attend Harvard. Saverin then writes the algorithm on the window of their Harvard dorm room.

Here is what the elo rating system equations look like: