Public-domain-equivalent licenses also known aspublic-domain-like licenses arelicenses that grantpublic-domain-like rights and/or act aswaivers. They are used to makecopyrighted works usable by anyone without conditions, while avoiding the complexities ofattribution orlicense compatibility that occur with other licenses.
No permission or license is required for a work truly in the public domain, such as one with an expired copyright; such a work may be copied at will. Public domain equivalent licenses exist because some legal jurisdictions[which?] do not provide for authors to voluntarily place their work in the public domain, but do allow them to grant arbitrarily broad rights in the work to the public.[2]
The licensing process also allows authors, particularly software authors, the opportunity to explicitly deny any implied warranty that might give someone a basis for legal action against them. While there is no universally agreed-upon license, several licenses aim to grant the same rights that would apply to a work in the public domain.
In 2000, the "Do What the Fuck You Want To Public License" (WTFPL) was released as a public-domain-equivalent license for software.[3] It is distinguished among software licenses by its informal style and lack of awarrantydisclaimer. In 2016, according to Black Duck Software,[note 1] the WTFPL was used by less than 1% ofFOSS projects.
In 2009,Creative Commons releasedCC0, which was created forcompatibility with jurisdictions where dedicating to public domain is problematic, such ascontinental Europe.[citation needed] This is achieved by a public-domain waiver statement and a fall-back all-permissive license, for cases where the waiver is not valid.[5][6] TheFree Software Foundation[7][8] and theOpen Knowledge Foundation approved CC0 as a recommended license to dedicate content to the public domain.[9][10] The FSF and theOpen Source Initiative, however, do not recommend the usage of this license for software due to inclusion of a clause expressly stating it does not grant patent licenses.[8][11] In June 2016 an analysis of theFedora Project's software packages placed CC0 as the 17th most popular license.[note 2]
TheUnlicense software license, published around 2010, offers a public-domain waiver text with a fall-back public-domain-like license, inspired by permissive licenses but without anattribution clause.[13][14] In 2015 GitHub reported that approximately 102,000 of their 5.1 million licensed projects, or 2%, use the Unlicense.[note 3]
TheBSD Zero Clause License,[16] published in 2013,[17] removes half a sentence from theISC license, leaving only an unconditional grant of rights and a warranty disclaimer.[18] It is listed by theSoftware Package Data Exchange as the Zero Clause BSD license, with the SPDX identifier0BSD.[19] It was first used by Rob Landley inToybox and is OSI-approved.
TheMIT No Attribution License, a variation of the MIT License, was published in 2018 and has the identifierMIT-0 in theSPDX License List.[20]
In thefree-software community, there has been some controversy over whether apublic domain dedication constitutes a validopen-source license. In 2004, lawyerLawrence Rosen argued in the essay "Why the public domain isn't a license" that software could not truly be given into public domain,[21] a position that faced opposition byDaniel J. Bernstein and others.[22] In 2012, Rosen changed his mind, acceptedCC0 as an open-source license, and admitted that, contrary to his previous claims, copyright can be waived away.[23]
In 2011, theFree Software Foundation added CC0 to itsfree software licenses and called it "the preferred method of releasing software in the public domain"[24][25] – the Foundation then reviewed its position specifically for softwares.
In February 2012, when the CC0 license was submitted to theOpen Source Initiative for approval,[26] controversy arose over a clause which excluded any relevant patents held by the copyright holder from the scope of the license. This clause was added with scientific data in mind rather than software, but some members of the OSI believed it could weaken users' defenses againstsoftware patents. As a result, Creative Commons withdrew their submission, and the license is not currently approved by the OSI.[27][11] In July 2022, theFedora Project deprecated CC0 for software code for the same reasons, but will still allow its use for non-code content.[28]
In June 2020, following a request for legacy approval, OSI formally recognized the Unlicense as an approved license meeting theOSD.[29]
Google does not allow its employees to contribute to projects under public domain equivalent licenses like the Unlicense and CC0, while allowing contributions to0BSD licensed andUS government PD projects.[30]
European copyright systems provide for a stronger connection between the copyright and the author of the protected work. This makes sense if one considers that even though the GermanUrheberrecht or the Frenchdroit d'auteur are often translated ascopyright, the literal translation isauthor's right. It comprises not only proprietary rights but also moral rights. In many European jurisdictions, only the proprietary rights are assignable; in others, copyrights, including the proprietary rights, cannot be assigned at all but authors may only grant others a license to exploit the protected work. Moral rights are usually not assignable and can be waived only to a limited extent.
The case you referenced in your email, Hampton v. Paramount Pictures, 279 F.2d 100 (9th Cir. Cal. 1960), stands for the proposition that, at least in the Ninth Circuit, a person can indeed abandon his copyrights (counter to what I wrote in my article) – but it takes the equivalent of a manifest license to do so. :-) [...] For the record, I have already voted +1 to approve the CC0 public domain dedication and fallback license as OSD compliant. I admit that I have argued for years against the "public domain" as an open source license, but in retrospect, considering the minimal risk to developers and users relying on such software and the evident popularity of that "license", I changed my mind. One can't stand in the way of a fire hose of free public domain software, even if it doesn't come with a better FOSS license that I trust more.
