As the name says, OpenTrivia is open for everybody. Open Sets are licensed under Creative Commons.

But there's a fine yet important distinction between open sets and authored sets, as the latter are copyrighted to their respective authors and may not be made commercial by other parties. (Currently, that's e.g. the authored set Movie Trivia copyrighted to me.)

What you can do is submit any questions to the open sets in any category, then download the data via the "Get/ View Trivia" link. When you republish them, please link back to http://opentrivia.com

An alternative is to download the Windows software OpenTrivia Creator for the development of authored sets which can be copyrighted to you. Authored sets don't belong in the public domain, but are copyrighted to the individual creator. You can simply make use of the editor and optimized storage format completely free of charge, and sell the authored sets in any type of application.

But again, the questions and answers of the open sets belong to the Creative Commons.

I would really like to see TriviaML being used by others, and in other applications, and if you need any support tell me.