If no open source license is given on a github account, what rules apply?

Question

The GitHub help pages says that

You're under no obligation to choose a license. It's your right not to include one with your code or project, but please be aware of the implications. Generally speaking, the absence of a license means that the default copyright laws apply. This means that you retain all rights to your source code and that nobody else may reproduce, distribute, or create derivative works from your work. This might not be what you intend.

Even if this is what you intend, if you publish your source code in a public repository on GitHub, you have accepted the Terms of Service which do allow other GitHub users some rights. Specifically, you allow others to view and fork your repository.

Would a forked repository be able to be used to produce something commercially?

Answer 1

I'll quote from my answer on a similar question from Programmers.SE:

...[T]he Github TOS have this to say about material hosted on their site:

By setting your repositories to be viewed publicly, you agree to allow others to view and fork your repositories.

Hosting on Github means that the author grants others the right to "view" and to "fork" the repository. Here, "fork" probably just means "use Github's fork feature", which creates a repository clone, hosted on Github.

GitHub's use of "fork" here probably refers to the software feature of the website github.com called "Fork," which allows users to create a verbatim copy of a repository on github.com.

The TOS do not require the author to grant any other specific rights, like the right to prepare derivative works or to redistribute copies of the work, so "fork" here probably is not used the general sense of "produce a derivative work." Thus, the code's presence on GitHub does not grant you rights to reuse the work in ways protected by copyright (commercial or otherwise) without a explicit license from the author.