> The core SQLite database software is in the public domain. No license is necessary to use SQLite or to build SQLite into your products. However, licenses are available to satisfy the following needs:
> - You want indemnity against claims of copyright infringement.
> - You are using SQLite in a jurisdiction that does not recognize the public domain.
> - You are using SQLite in a jurisdiction that does not recognize the right of a authors to dedicate their work to the public domain.
> - You want to hold a tangible legal document as evidence that you have the legal right to use and distribute SQLite. Your legal department tells you that you have to purchase a license.
To be more specific. Public domain is intended to mean "after copyrights have expired". It is not a sort of license that can be put on a creation.
I can't recall who it was now, but I remember reading about an open source project that makes considerable money from selling these licences, even though they weren't necessary (the licence was MIT). The licence even had an explanation around it stating (paraphrasing) "Hey, this isn't required, but if it makes you feel better, you can pay for it".