What is Cloud Computing?
Cloud computing is the Internet-based revolution of computer technology. Cloud computing is significant because it marks the movement from PC-centered computing to web-centered computing. Instead of relying solely on laptops and desktops for storing data or running applications, users of cloud computing can use applications provided on the cloud, or the Internet. You are already participating in cloud computing if you use web applications such as Facebook, Flickr, or Google Drive.
Since applications like the ones mentioned above run on the cloud, they can be accessed at anytime and anywhere. This is just one of the many benefits that result from the flexibility of cloud computing. Cloud computing is not only useful to end users, but it provides many benefits for web application developers and businesses that provide services over the cloud.
There are three major forms of cloud computing: applications in the cloud, platforms in the cloud, and infrastructure in the cloud. 1
Applications in the Cloud
Applications in the cloud are services like Gmail, Yahoo! Mail, Google Drive, Wikipedia, and search engines. Users can sign in and use these programs or services over the Web. This is sometimes referred to as SaaS, or Software as a Service. 2
Applications that Use Cloud ComputingApplication DescriptionDropboxOnline file storage and sharingGmailGoogle's web-based email serviceGoogle DocsOnline editing and storage of documents, spreadsheets, presentationsWikipediaCollaborative, non-profit, Internet-based encyclopedia
Platforms in the Cloud
These platforms are often for developers. They allow programmers to code to specific Web application program interfaces (APIs) that a host specifies in order to have a Web application run on the Internet without any server costs. This is a newer area of cloud computing, and is a very interesting addition to the Internet. A few examples are the Google App Engine and Force.com. Sometimes this is called Platform as a Service (PaaS). 3
Infrastructure in the Cloud
This idea involves moving virtually all computing tasks (including the operating system and desktop manager) to the Internet or network, and then having thin clients that are little more than a keyboard, monitor, and mouse hooked up to the Internet. Thin clients use very little electricity and require almost no maintenance when compared to normal desktop. This, coupled with the centralization of applications to cluster or grid of servers, allows for companies to cut back on IT costs across the board. This is sometimes referred to as IaaS: Infrastructure as a Service. 4
Where Can I Learn More?
This CNN article is good, but the video at the top of the page is even better.
Here's another great article about how cloud computing works.
For businesses, Microsoft provides companies with basic to comprehensive definitions of cloud computing.