I received a request today in the mail about one of my projects that is available under a free software license. It's a web template system that I wrote to scratch a personal itch. Its hallmark feature is that it has no features, at least none that contribute to the bloat that's rampant in Drupal and Joomla and their ilk.
His email was very well-written, asking about some of the specifics of the license, and how he could undertake projects for his clients building upon my framework. After I wrote a detailed reply to him, it seemed like a good idea to post it to my blog, for there are many who're not particularly clear on how free software licensing works.
I want to use your templating system to build static websites for personal and commercial projects. I don't have lots of money so I can't promise much now but later if I will be able to make any money I will happily donate for this project.
I like open source projects because it is fun to learn how magic happens. I don't want to use your code without permission because I just personally don't think it is right thing to do. I have no problem giving you credit for this system but I need your permission to use it for commercial use?
And my reply:
I'm glad you found the site and my projects interesting and useful, and thanks so much for writing back to let me know!
I think free software is a great way to learn and understand other people's code, that's why almost all of my projects are open-source with the license to tinker and play. All I ask in return (via the Creative Commons license) is attribution back to me if you use it in a project. I've licensed this as an Attribution-ShareAlike-Noncommercial license, so you're free to use it as you wish in any personal project as long as it is non-commercial: e.g. for an organization you belong to, or an academic department or program.
Things get a little more interesting when money enters the picture. While I'm not doing this (releasing my software) for the express purpose of making money from it, it does not seem right to me that someone else benefit financially from my work with no benefit to me. So, I politely ask that if you're planning to use this commercially, you should contact me for a separate license (the code will then be dual-licensed, and you can pick either the paid commercial license, or the default un-paid non-commercial one.)
You don't have to pay anything right away, and can play with the code as much as you want. But when you bag a client who wants to use a system based on my code, we can talk about royalties. That way, you retain the freedom to examine and modify my code as well as get a paying client, and I do not feel that someone has taken undue advantage of my generosity. This is how the open-source model was intended to work, and the free really refers to freedom, not free as in no-charge.
I'm glad you contacted me to check for permission first, and I got the opportunity to clarify. Often it's quite tricky, and lots of people have lots of misunderstandings about how free software licenses work.