"Unlimited websites" includes websites for clients' projects (commercial). "Resale in product" means distributing the plugin in an application/product (ex. CMS) for sale (this includes usage in SaaS project).
Other question: How can you use a JS library without having the source? ... I mean, how do you make sure that it remains closed source? As far as I know obfuscating and minifying is very easy to overcome. Do you have any special techniques?
