You can run Paid Memberships Pro on as many sites as you want. The PMPro code is not obfuscated, so you can customize it to fit your needs or use the code in your own projects.
In fact, you can do pretty much anything you want with the PMPro code as long as you follow the GPLv2 guidelines by applying the GPLv2 license to any altered or unaltered version of PMPro that you distribute.
If you are using an altered version of PMPro in one of your projects, we do ask that you:
- Give your software a name other than “Paid Memberships Pro” or “PMPro” to avoid confusion.
- Notify us of your distributed version so we can potentially promote the distribution if it’s a good effort.
More information on why we’ve settled on this license can be found in our blog post here.