Not sure how to weigh your application, if it is a normal program then GPL3 will probably be a good choice: http://en.wikipedia.org/wiki/GPL http://en.wikipedia

Not sure how to weigh your application, if it is a normal program then GPL3 will probably be a good choice: http://en.wikipedia.org/wiki/GPL http://en.wikipedia.org/wiki/GPL If you want to protect the users of service then probably GPL3/Affero will do the job: http://en.wikipedia.org/wiki/Affero_General_Public_License http://en.wikipedia.org/wiki/Affero_General_Public_License If these won't do it then either search on or wait for better answers. Success! Edit: These licenses like most open source licenses will not prohibit people from forking your software nor will they prohibit commercial interaction, they simply protect the rights of your users. What you probably want is trademarking your brand.