What Does It Mean?
In a nutshell, Cloud Computing (also known as Cloud Software or Software as a Service (SaaS)) means that both your software and your data is stored somewhere on the internet.
You access your software and data through an internet connection and any web browser.
Why is that Good?
The advantage of this is that your information is always available to you - all you need is an internet-connected computer or mobile device (if supported).
You don't need to install any special programs on the computer you're using to access your information (other than standard browser plug-ins like Microsoft Silverlight or Adobe Flash).
You also don't need to purchase any expensive server or database software - which typically run tens of thousands of dollars!
Your business information and functionality is available to you from anywhere as long as you have an internet connection. No custom software installation is required for you to run your business.
Even better, software upgrades and new functionality are automatically available to you every time you log in to your application - no need to download annoying updates and patches!