In its most simple description, cloud computing is getting services; software and computing resources, delivered over the Internet as a service. Applications and services; data and programs, are access and stored via the Web, instead of your hard drive.

These services are usually paid for on some kind of usage or subscription basis, typically on “as-needed, pay-per-use” business model. The cloud infrastructure is maintained by the cloud provider, not the individual cloud customer. Stop paying, and service is cut off.

But, don’t get confused, “The Cloud”, is not another term for “Internet”. It is possible to use the Internet without using cloud services and it is possible to be on a cloud without being on the Internet. Storing data on a home or office network does not count as utilizing the cloud. For it to be considered "cloud computing," you need to access your data or your programs over the Internet, or at the very least, have that data synced with other information over the Web.

Common Cloud Examples:

 The Cloud it is part of almost everything on our computers these days.

Google Drive: This is a pure cloud computing service, with all the storage found online so it can work with the cloud apps: Google Docs, Google Sheets, and Google Slides. In fact, most of Google's services could be considered cloud computing: Gmail, Google Calendar, Google Maps, and so on.

Apple iCloud:  Apple's cloud service is primarily used for online storage, backup, and synchronization of your mail, contacts, calendar, and more. All the data you need is available to you on your iOS, Mac OS, or Windows device. Apple’s iCloud allows you to store music, documents, photos, and other files via Wi-Fi. You can access them from all of your devices. iCloud is also the place iPhone users go to utilize the Find My iPhone feature, when the handset goes missing.

Amazon Cloud Drive:  Storage mainly for music, preferably MP3s that you purchase from Amazon, and images. Amazon Cloud Drive also holds anything you buy for the Kindle.

IBM Smart Cloud: Provides numerous services for IT companies, such as developing applications in the cloud or using the cloud as a backup for your company files.

In fact, most of us use cloud computing all day long without realizing it. Preparing documents over the Net is an example of cloud computing. Simply log on to a web-based service such as Google Documents and you can create a document, spreadsheet, presentation, or whatever you like using Web-based software. Instead of typing your words into a program like Microsoft Word, you're using similar software running on a PC at one of Google's world-wide data centres. Like an email drafted on Hotmail, the document you produce is stored remotely, on a Web server, so you can access it from any Internet-connected computer, anywhere in the world, any time you like.

Types of Cloud Computing

 Cloud-computing providers offer their "services" according to different models, of which the standard models are:

Software as a Service (SaaS).  The capability provided to the consumer is to use the provider's applications running on a cloud infrastructure. The applications are accessible from various client devices through either a thin client interface, such as a web browser or a program interface. Which means, you use a complete application running on someone else's system. Applications samples: CRM, Email, Virtual desktop, Communications, Games…

Platform as a Service (PaaS).  In this platform, cloud providers deliver a computing platform, typically including operating system, programming-language execution environment, database, and web server. The consumer does not manage or control the underlying cloud infrastructure including network, servers, operating systems, or storage, but has control over the deployed applications and possibly configuration settings for the application-hosting environment.

So for example, you might develop your own ecommerce website but have the structure, including the shopping cart, checkout, and payment mechanism running on a merchant's server. Examples of PaaS include Google App Engine, Microsoft Azure, Amazon Web Services and Salesforce.com

Infrastructure as a Service (IaaS). This is the most basic cloud of them all, where you rent the hardware, storage, networks, and other fundamental computing resources, which can include operating systems and applications. Because you're buying access to raw computing hardware over the Net, and you buy what you need and pay-as-you-go, or you only pay for the computer resources you use, this is often referred to as utility computing.

Public or Private Cloud:  A cloud is called a "public cloud" when the services are rendered over a network that is open for public use. Web-based email and free services like the ones Google provides are the most familiar examples of public clouds. The world's biggest online retailer, Amazon, is one of the world's largest provider of public cloud computing since early 2006.

 “Private cloud " is cloud infrastructure operated solely for a single organization, whether managed internally or by a third-party, and hosted either internally or externally. Private cloud computing works in much the same way as Public cloud, but you access the resources you use through secure network connections, much like an Intranet.

What is the big deal about Cloud Computing?

 Advantages

Because companies share the infrastructure, cloud computing makes it super cheap for anyone to access enormous computational resources. Rather than spending thousands to own your own computer and networks, you can rent all the power you want for however long you want it. Cloud computing allows you to buy in only the services you want, when you want them, cutting the upfront capital costs of computers and peripherals.

 Unfortunately, instant convenience comes at a price, so its fair to say, Cloud Computing brings some limitations and disadvantages.

Disadvantages

According to Bruce Schneier, an American cryptographer, computer security professional, privacy specialist and writer; “The downside is that you will have limited customization options. Cloud computing is cheaper because of economic scale and – like any outsourced task – you tend to get what you get”. He also suggests that "the cloud provider might not meet your legal needs" and that businesses need to weigh the benefits of cloud computing against the risks.

With Cloud Computing, the control of the back end infrastructure is limited to the cloud vendor only. Cloud providers often decide on the management policies, which moderates what the cloud users are able to do with their deployment. Cloud users are also limited to the control and management of their applications, data and services.

Security has always been an obvious concern for people who use cloud computing. Perhaps surprisingly, security has been seen as a compelling reason to migrate to cloud-based systems rather than a reason to avoid them. Many IT professionals think cloud-based systems are actually more secure than conventional ones. Security has improved over the years; with many companies using email encryption and SSL enforcement for secure HTTPS access, among other security measures. We understand what we mean by keeping data secure. But, what about privacy? Can the Cloud keep data private in a world where users of cloud based services and platform like Twitter, Instagram and many more, shares happily everything online?  

Privacy is a bigger complex issue. Companies like Google and Facebook, collects huge amounts of data through its advertising platforms and no-one knows exactly what happens to it afterward. Facebook have detailed profiles of all its users. We all know that hackers are spending substantial time and effort looking for ways to penetrate the cloud. We all have heard cases of security breach, passwords stolen and private information leakage to mention some.

Cloud computing comes with the risk that unauthorized users might access your information. To protect against this happening, cloud computing services offer password protection and operate on secure servers with data encryption technology.

 Conclusion:

Whether you use your devices as an individual or as a company, you can take advantage of cloud computing. If you are using Apple devices, Apple’s iCloud can be particularly useful to you. Small businesses, in turn, can opt to share documents via Google Cloud Connect, Google Docs, or Dropbox. IT and application development teams should opt for more complex services, such as those provided by IBM Smart Cloud.

 Cloud computing is a relatively new technology that will only become more widespread. It offers many advantages that could immediately benefit you and your business. However, Cloud computing is still a subject of research, and initial developments come with frequent drawbacks. Many of us are still a little suspicious of the cloud and the risks it brings, but we are getting over it thanks to the number of cloud products and their low cost. Plus, if you wait a while, the service will likely develop more fully as problems are washed away and cost will go down as more people adopt the technology.