I am proud to report that yesterday JustinYan, a graduate student from the LeBuSiShu team, suggested that I will join their team.
The reason is that LeBuSiShu is using GraphLab ALS solution as one of the components in their final result. Currently LeBuSiShu is the 5th group in the leaderboard (out of 100 groups!) with RMSE = 22.2820.
Anyway, of course I was honored to accept as well as quite excited! Although when writing the GraphLab collaborative filtering code of matrix factorization I had no competition in mind, it is always nice to know that someone finds your solution useful.
Besides of JustinYun, another nice team member in the LeBuSiShu group is: Yao Wu, National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academic of Sciences.
A quick update 6/23: We are actually now at the 4th place! The Chinese group is an amazing team, they simply work around the clock. I myself am running some fancy MCMC methods for slightly improving prediction, but the Chinese team is responsible of 99.9% of the progress.