Fourth Ray Software sells a license to an application which allows you to use that application with certain conditions and restrictions (see the application's license agreement).
A license is a written, legally-enforceable agreement between Fourth Ray Software and you, the user of the software application. It protects both the company, and you, and sets up certain, clearly-stated agreements. A license allows you to use the software, but you don't actually own the software. Ownership remains with Fourth Ray Software, the creator and publisher of the software. In other words, you can use the software, but you don't have the right to the source code and tools that go into generating the software, nor being able to redistribute it yourself.
For our paid-for software applications, Fourth Ray Software grants you a one-time, 21-day trial period, during which you can use the product for free. After that you must pay for the license for the right to continue to use the application. This is fundamental to the way Fourth Ray Software conducts its business, and provides income for the company to continue to enhance existing products and create new software applications (and to pay the bills, of course). Our free-to-use (a.k.a. freeware) software application do not have that 21-day trial period; you are free to use those applications for as long as you please. Their license stipulate some restrictions, though.
Licensing can be confusing, because it involves legal "stuff". However, it is fairly straight-forward. If you are the only one using your computer, and you are the only one that will be using this application, you only need one license. If you have a computer that is used by other family members or a "communal" computer in a small office setting, then you only need one license, because only one person can be using the application at a time. And this is the crux of our licensing: how many people in your family or office could be using this application at the same time? That is how many licenses you need. Therefore, if you put our application on an office server, and people at different workstations have access to the application, then you need as many licenses as there are people who have potential access to the application, because, in theory, every one of those people can be using the application at the same time.
Your one-time license fee pays for all the research and development we put into the application before you downloaded it, and the time we will invest into it in the future.