We don't mind if you're are using the software for personal use and have a few machines, e.g. a Desktop and a laptop and you want to use the software on those machines, thats fine, so long as it's not being used at the same time on those machines. We're not happy campers if you use the same code on 50 machines at the same time. That's called a site license.
If you're using the software in a business/commercial capacity then you will need to by a license for each machine that you want to use the software on.