1. Introduction
Today, people and systems overload the web with an exponential generation of huge amount of data. The amount of data on the web is measured in exabytes and zettabytes. By 2025, the forecast is that the Internet will exceed the brain capacity of everyone living in the whole world. This fast growth of data is due to advances in digital sensors, communications, computation, and storage that have created huge collections of data. The term Big Data had been coined, by Roger Magoulas, to describe this phenomenon.