Cloud computing involves delivering computing services over the internet. It has three main components - clients that users interact with, distributed servers that host applications, and datacenters that administer the system. There are different types of cloud services including Software as a Service (SaaS), Platform as a Service (PaaS), and Infrastructure as a Service (IaaS). Cloud services can be deployed publicly, privately, or as a hybrid model. Cloud computing is popular because it offers scalability, reliability, efficiency and reduces complexity compared to local computing resources.