Cloud computing involves delivering computing services over the Internet. Instead of running programs locally, users access software and storage that resides on remote servers in the "cloud." The concept originated in the 1950s but Amazon launched the first major public cloud in 2006. Cloud computing has three main components - clients that access the cloud, distributed servers that host applications and data, and data centers that house these servers. There are different types of clients, deployment models for clouds, service models, and cloud computing enables scalability, reliability, and efficiency for applications accessed over the Internet like email, social media, and search engines.