Implementing libFM in Keras (IT Best Kept Secret Is Optimization)

I just won a gold medal on Talking Data competition on Kaggle, finishing 6th. My approach and solution is described here. The part that triggered most interest from readers is where I used matrix factorization techniques to generate additional features. Before that, let me briefly explain what this competition was about. To support your modeling, they have provided a generous dataset covering approximately 200 million clicks over 4 days!