It does seem strange that the only reward is a chance at an interview. Most other contests at Kaggle at least offer something tangible. One of the first contest

It does seem strange that the only reward is a chance at an interview. Most other contests at Kaggle at least offer something tangible. One of the first contests at Kaggle was a chess ratings prediction which offered signed book by Kasparov, Karpov et al. I suppose it is one way to weed out those who would not be likely to apply to Facebook even if they did well at the contest.