If you purchase one license, please enter one production domain - If you purchase two or more licenses, please enter two or more production domains separated by a COMMA (,).
One license is valid for ONE Magento instance/installation production site, 3 development site admin domains, and unlimited frontend domains. Please make sure the development URL is clearly marked as a development URL (sub-domain containing dev or staging or test, just anything that cannot be used productively, for more information please check our wiki).
If you want to add more sub-domains after you've already got the key license, please email us: firstname.lastname@example.org. We're willing to add for you.