This document provides an overview of cloud computing, including what it is, the services it offers (IaaS, SaaS, PaaS), types of cloud (private, public, hybrid), advantages for businesses and developers, and market projections. Cloud computing allows companies to host data and applications on massive computing utilities managed by third parties. It is predicted that over half of businesses will rely on cloud computing by 2020, and the global cloud market will reach $241 billion by then.