Whether it’s a private cloud or a public one, and even if you don’t know what or where that cloud is, chances are, you’re probably already using it.

Cloud computing is a general term referring to any kind of service hosted over the internet. More specifically, cloud services refer to hosted services which are located in big blocks of servers in one or many places around the globe and are accessed over the internet. These server blocks are considerably larger than those found in any one company, and provide servers for multiple companies simultaneously.

The nebulous name was inspired by the symbol traditionally used to represent the internet on diagrams: a cloud.

There are many different versions of cloud computing, of course. Companies pay a certain amount per month for use of the internet service, such as software as a service (SaaS), platform as a service (PaaS) or storage as a service (StaaS). In the case of SaaS, a hosting service provides and manages software and makes them available to companies of all sizes using a central server.

What this means is that companies no longer have to worry about what versions of software have been installed on a particular machine or at a particular location because users can simply log on to the host site and access what they need from the cloud. For start-ups especially, this can be a financial godsend.

Cloud Service Providers (CSPs) can be either private or public. A private one only offers its services to a limited number of customers but a public cloud sells its services to anyone on the internet.

Naturally, companies don’t really want people to know exactly how many servers are being used to host their services. However, Amazon Web Services is believed to be the largest public cloud provider, running an estimated 450,000 servers. Other companies, like IBM, Microsoft and Salesforce, are big players in the field as well.

Probably the most frequently used cloud service is Google, which offers its software and services free to billions of users worldwide in the form of email, photo sharing, online productivity tools and even website creation tools.

There are drawbacks to these services, of course. Cyber security is the most vexing concern. The increasing use of Web 2.0 technologies and collaborative work make the concept of keeping information absolutely secure a problematic issue no matter where data is stored.

Giving up complete control of private data is another reason cited by companies for not yet embracing the cloud. In other cases, the need for restructuring the company in order to accommodate the cloud is too daunting a task. And what happens if the power goes out? While uncommon, a power or internet outage could be very damaging.

Ronald Rivest, a professor of computer science at MIT, thinks part of the problem is cloud computing’s rather innocuous name. He believes terminology plays a crucial role in how we perceive a particular technology. ‘If we go around for a week calling it swamp computing, I think you might have the right mindset.’