Cloud computing is the concept of using computing resources over the internet.
The title "cloud" in computing parlance is an abstraction of the complex internet infrastructure; that the end user need not worry to know about, as long as his computing requirements are met with.
Cloud computing users (customers) do not generally own the physical infrastructure that they are using. They just pay for the services that they consumed.
So, Cloud Computing essentially saves the companies from huge Capex that they otherwise had to incur for their computing needs
Typical Cloud Computing Services that are available in the current market are:
Software As A Service (SaaS)
Platform As A Service (PaaS)
Infrastructure As A Service (IaaS)