The Unlicense vs CC0
When comparing The Unlicense vs CC0, the Slant community recommends CC0 for most people. In the question“What are the best 'public domain' open-source licenses?” CC0 is ranked 2nd while The Unlicense is ranked 3rd. The most important reason people chose CC0 is:
https://www.gnu.org/licenses/license-list.html
Ranked in these QuestionsQuestion Ranking
Pros
Pro Short and simple
The Unlicense is just 3 paragraphs long.
Pro It helps removing the conflicts and violence present in the world
Simple, negativates intellectual property, doesn`t falsely legitimate government coercive threats against other humans not mattering what they have done with their code. You can be sure that using it you avoid "my property, it's mine, ok? I just left it for you to use under my conditions, I own it, I wrote it in that file, it makes sense, my government also says so, now die or I'll kill you."
Pro Removes any possible licensing issues
Everything under the Unlicense is part of the public domain, which means that anything can be done with it.
Pro Unlicensed code is easy to find
When using public code hosts such as GitHub and BitBucket it is suggested to use the filename UNLICENSE instead of the more traditional LICENSE or COPYRIGHT to store the license so it's easier to find unlicensed code. Additionally, the first line of the license is worded in a unique way specifically to allow searching for it with search engines.
Pro Protects the author
The author of the software avoids any risk for how the software may be used by others.
Pro Recommended by the Free Software Foundation
Pro Compatible with the GNU GPL
Cons
Con Gives no control of how the code is used
Putting the code in the public domain leaves it open to abuse.
Con Hasn't been reviewed by OSI
The OSI (Open Source Initiative) is an organization that promotes open source software and they commonly review open source licenses. However, they have decided not to review Unlicensed because it has not been written by legal professionals.