Put simply it is an Integrated Development Environment (IDE) that provides a simple programming framework that can be deployed to PalmOS or PocketPC. This simplicity leads to it being labeled Rapid Application Development (RAD) tool.
Why is Satellite Forms a preferred option? From my perspective the time to install and configure other development environments is many hundreds of times longer than setting up Satellite Forms. Also, most applications are simple - and this is where Satellite Forms is advantageous, it allows you to quickly do simple programming quickly.
You can find out more form the official web site.
My products added some more advanced features such as encryption. They were limited to the PalmOS, also known as Garnet OS and had the last release in 2007. So - is PalmOS dead? Yes - the PalmOS is all but dead, with the company that owns it replacing it with Access Linux Platform. Even Palm (the hardware company) have stopped using PalmOS, switching to webOS instead, which is also Linux based.
But how does this affect Satellite Forms? Well, the good news is that anything made for PalmOS will work on Access Linux Platform and webOS. This re-opens the potential for Satellite Forms on these devices, and strengthens it's position as not only one of the oldest of the PalmOS development environments, but also one of the few cross-platform development environments.
My assumption is that Satellite Forms can now deploy to Microsoft based systems, PalmOS, webOS and Access Linux Platform.