If you were going to design an optimal protocol from scratch today, you would not make TCP/IP or HTTP (check the Referer header [0]) or lots of other things. Bu

If you were going to design an optimal protocol from scratch today, you would not make TCP/IP or HTTP (check the Referer header [0]) or lots of other things. But we all use them to maximize interoperability. For the same reason, you should almost certainly be using the MIT, Apache, or GPL license to maximize the chance that your open source software can actually be used by others. If you don't use a well known license, very few will invest in the lawyer's time necessary to evaluate your custom license. (See the problems caused by the tongue-in-cheek JSON license: http://tanguy.ortolo.eu/blog/article46/json-license http://tanguy.ortolo.eu/blog/article46/json-license ) Use the dominant license for your project (e.g., MIT for Ruby Gems). For new projects, I recommend http://choosealicense.com http://choosealicense.com to pick a license. [0] https://en.m.wikipedia.org/wiki/HTTP_referer https://en.m.wikipedia.org/wiki/HTTP_referer