Learn more about the concept of "copyfree": http://copyfree.org An often-heard argument made by copyleft enthusiasts is the situation of a company taking non-copyleft code and using it in a (closed-source) proprietary project. Presented are the counter-arguments: 1) The user is likely to submit back changes - after all, why try to keep up with the upstream yourself if you can have others do the code merging - FOR FREE! 2a) Even if they don't do '1)', they have to provide attribution, ergo - - PROFIT! 2b) If they are too stupid to realize the benefits of letting someone else maintain (and improve) their code, let them suffer. 3) If they don't have many users, they're losing money anyways, so they haven't benefited from your license. 4) If they don't like your license, they won't use your software, which is worse than if they HAD used it and you got part of their traffic/customers. The distribution of this memo is unlimited.