Cloud computing is an emerging trend where computing resources like data storage and processing power are provided via the internet rather than being hosted locally. There are three main types of cloud services - Infrastructure as a Service (IaaS) which provides basic storage and networking capabilities, Platform as a Service (PaaS) which provides servers and hosting environments for applications, and Software as a Service (SaaS) which provides applications delivered over the internet. Cloud computing provides advantages like reduced costs and maintenance compared to locally hosted systems, but also disadvantages around internet dependence and security.