Data is changing our society. Because of data we are rethinking our industries to build better products: agriculture, education, finance, legal, etc. With the advent of data, a prodigal son of the machine learning family has returned to the fore to play a main role: artificial neural networks, also known as Deep Learning. In this talk, I will provide some insights about its application to detect fraudulent credit card transactions conducted in online stores and retailers. I will also describe the data we use, how neural networks are trained and how their performance is measured. Besides, I will discuss more general thoughts about how the possibility of processing huge amount of data has boosted deep learning and machine learning in the industry.