A: The answer is both simple and complicated. I think I can break it down for you, though.
(Although if you just want complicated, go straight to Wikipedia.)
When talking about the Internet, I tend to throw around terms like “server” and “client” without much explanation of their meanings. Let’s take a moment to attach some meaning to these terms, because they are essential to an understanding of the cloud.
A server is just a computer that holds information for other computers to access. A client is a computer that access information on a server. To make that more concrete, consider the website you are looking at right now, and the device you are using to access it.
Most of the information you are looking at right now is hosted (“hosted” just means “stored on”) on a server in Chicago. The computer — or tablet or phone — you are currently using to see the information is a client. At the same time you and your client are accessing information on our server, dozens of other people are doing the same thing. Our server can handle hundreds of simultaneous connections.
It is the same thing with everything you do on the Internet. Everything you access online is hosted on a server somewhere. Those servers run software the business of which is sending information to your browser where it can be displayed. The software that displays Lawyerist to you is called WordPress, which is installed on our server and assembles Lawyerist’s posts and pages and gives them to your browser, which deciphers them and displays them on your screen. You probably don’t think of Lawyerist as software, but it is, even if it is fairly simple software.
Well, it’s more complicated than that, actually. Some of the information you are looking at, like the images on this page, are hosted on other servers running other software. WordPress actually goes and gets those pieces of our pages and assembles them for your browser. Although your browser does some of the work, too, because sometimes WordPress just tells your browser where to get things, instead of actually providing the thing.
This may all sound very complicated, and it is. There is an elegance to the cloud, but the point is this: it does not really matter to the client — your computer — where the data comes from, geographically. The point is that it gets to your computer where the user — that’s you — can use it. The data might come from one server in Chicago, another server in San Antonio, and another server in Bombay. Those choices are made by the person who set up the website you are accessing.
That’s all the cloud is: a lot of servers connected to the Internet (the cloud goes beyond the Internet, but that’s good enough for our purposes). And the Internet is just a network of wires and wireless signals that you can access from your computer or tablet or phone. Every website you visit is a connection to a server (or more than one server) somewhere in the cloud. Those servers can deliver software to clients as easily as web pages, and cloud-based software (“software as a service” or “SaaS”) is usually the reason why people are asking about the cloud.
SaaS is actually quite simple. Instead of installing software on your computer, all you have to do to use SaaS is type a URL into your browser. The software runs on the server, and you see its output in your browser. If you have ever used Gmail or other Google Apps, Freshbooks, QuickBooks Online, Clio, MyCase, Rocket Matter, Basecamp, or hundreds of other browser-based software, you already know what SaaS is, even if you have not thought of it that way. In fact, the difference between editing a document in Microsoft Word and in Google Docs is a pretty good comparison:
One is in the cloud, the other is on my computer. Same result, essentially.
Just like this website, SaaS is software hosted in a server that you access through a client. It shows up and you use it through a browser. There are a lot of good reasons why SaaS has become so popular, but that’s a topic for a future FAQ post.