Introduction
Today there is great interest in the technology class BIG DATA, connected with the continued growth of data that have to operate large companies. The accumulated information for many organizations is an important asset, but handle it and benefit from it every day becomes more and more expensive. In my essay, I will try to describe the concept of "big data" and explain how it works.

What "Big data" means?
The concept of big data is rapidly gaining popularity. However, the exact idea of what constitutes a concept is not at all, especially for people outside the IT-sphere. The easiest way to explain this ignorant man on a practical example.
Two years ago, a huge network of Target stores began using machine learning in the interaction with customers. As a training sample used data collected by the company for several years. As markers of specific customers to use banking and nominal discount cards. Algorithms analyze how and in what conditions were changing consumer preferences, and make predictions. And, on the basis of these forecasts, the buyer makes all sorts of special offers. In the spring of 2012, a scandal broke out when the father of twelve years old school girl complained that his daughter sent leaflets with suggestions for pregnant women. When the network is already prepared Target recognize the error and apologize to the aggrieved customers, it turned out that the girl really was pregnant, even though she and her father at the time of the complaint did not know about it. The algorithm has caught behavioral changes women customers, specific to pregnant women.
Signs of Big Data: * Volume: really big (although the size depends on the resources available for processing). * Variety: poorly structured and diverse. * Velocity: processing is necessary to very quickly (and often the results are needed quickly when talking about online