The cloud is made up of large groups of powerful computers called servers. They're usually housed in data centers or computer rooms, and these centers are running software that can distribute processing over their network across multiple servers. Users access cloud services remotely via their own web browsers. In fact, you could consider anything you can get to on the Internet to be in the cloud, since you're accessing the data on a remote server. And a lot of the media you're streaming these days is in the cloud.
The advent of cloud computing gives businesses the potential to quickly increase their processing capabilities without having to buy equipment or hire and train new staff, and often at lower cost than in-house IT expansion would require. Companies simply pay a host for whatever type of access and services they need. These types of services also mean that smaller businesses and startups that never would have been able to raise the capital to buy heavy-duty equipment and the necessary staff can gain quick access to computing power.
Types of cloud services you can purchase vary from simple data storage to server space on which you have to do most of the IT work yourself (albeit remotely) to fully realized software systems that you and other users can simply log into and use. Cloud computing is altering the way we consume and purchase business software and hardware. Having lots of your data in the cloud also allows data mining for business analytics.
You don't have to be a business to utilize the cloud. The wide availability of inexpensive broadband connectivity means many of us are always online and able to access data much more quickly than in the days of dial-up. You may already be using an online e-mail service like Gmail or Hotmail, online office software like Google Docs, or storing your photos, videos or documents on storage sites like DropBox, and you just didn't know to call it the cloud.
Storage space used to be expensive, but it's getting cheaper and cheaper. Many cloud services will give you several gigabytes of storage for free and charge you annual or monthly fees if you need more space. Anything that you store on them can be accessed from multiple devices and from any location with an Internet connection. It also makes it easy for people to travel light, or to share data with others.
Our always-on connectivity, along with a shift to downloadable software (also made possible by cloud storage), is allowing us to swap our heavier desktop and laptop computers for smaller, cheaper devices with less storage like netbooks, tablets and even phones. We can get to all our data online.
Possible drawbacks to moving things off of a local hard drive are the security of personal information, loss of data if something goes wrong (say your cloud provider goes under) and loss of access when you have connectivity issues. But physical hard drives can be lost, as well. The best solution is to keep anything you don't want to lose in more than one location, and that makes the cloud a good backup solution. If a computer or physical hard drive fails, the information can be downloaded from your cloud service to new devices.
Many of our phones now automatically sync our data to a cloud account so that we never have to worry about plugging them into our computers to upload or download data. If your phone is lost or stolen, in many cases you can wipe its data remotely and then reinstall everything easily onto a replacement.