I have just read the Magento Commerce Software License Agreement v1. (Https://magento.com/sites/default/files/magento-commerce-software-license-agreement.pdf)
Under Section 2B it says
Customer may (g) use any copyleft software in conjunction with
Does that mean that I can not use open source modules or extensions in Magento Commerce? As far as I know, all common open source licenses are OSL Copyleft.