Johnny

Weird/confusing name, questionable legality and the website went down a while back (while mentioned explicitly in the licence…)

Use CC0 1.0 or Zero Clause BSD instead. They are more reputable, and all decent “public domain equivalent” licences are… well, equivalent in effect, anyway.

CC0 is the one CC licence you can safely use for code, as per the official recommendations. For all other CC licences, it is (strongly) discouraged.

RE: Copyleft

The idea of copyleft is that you give anyone the freedom to do anything with your work, with one essential restriction: they do the same for their changes, derivative works etc. Technically attribution doesn’t have to be part of a copyleft licence, but all copyleft licences I know have a requirement to preserve copyright info.

And yes, it is popular in software (GPL, MPL, EPL), but for other types of works there is CC BY-SA 4.0 (Creative Commons Attribution-ShareAlike). If you want to copyleft books, images, videos, other forms of text… this is the way to go, IMO.

Some additional remarks, just to clarify:

• Copyleft is not “giving up all copyright” - copyleft essentially “plays” the copyright system in a way that makes sure nobody is restricting access to or usage of one’s work. Using the rules of copyright against copyright, if you will.
• In some jurisdictions, there is no such thing as “giving up all copyright” or “dedicating something to the public domain”. Best you can do, generally, is giving users all the same/relevant rights.
• Most Creative Commons licences are not copyleft, only the ones with a ShareAlike (SA) clause. Some CC licences are also nonfree, meaning they don’t give you all the freedoms to do what you want with the work. The 2 possible nonfree clauses in CC licences are ND (no derivative works) and NC (no commercial use). NC can also be used together with a SA clause, making CC BY-SA (free) and CC BY-NC-SA (nonfree) the two CC copyleft licences.

Check out https://github.com/massgravel/Microsoft-Activation-Scripts