The license basically allows anyone to do whatever they want with the code as long as the original copyright and license notice is included along with the copy of the code. The code can be used for commercially, privately, it can be modified and it can be distributed.
The MIT/Expat license doesn't protect against open-source code being taken (without payment) and used in proprietary software. This is harmful to user freedom because it lets future development be taken out of the public domain and instead moved into non-free programs.
In addition, it doesn't protect against software patents being used to attack user freedom. Unlike the Apache 2.0 and GPLv3 licenses, the MIT/Expat was written before software patents became a problem and doesn't include a patent release.
Requires people building on your work to license it the same way you did. Good if you want to pull their code into your project, but issues for potential end users can arise.
The license basically allows anyone to do whatever they want with the code as long as the original copyright and license notice is included along with the copy of the code. The code can be used for commercially, it can be modified and it can be distributed.
Software licensed under the GNU GPLv2 is incompatible with all other licenses, with the exception of GPLv3 in most cases. This means that code from a GPLv2 program cannot be combined with code under another license in the same program.
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."
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.
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.
It has been used in many open source projects, but is not fully validated, although widely accepted as an open source license.
i.e. Proven in a court of law.
It requires change of files, so if you are making a copy of any software licensed with this license, you will have to PROVE that it is not the original software under another name. You are permitted to use the Standard Version and create and use Modified Versions for any purpose without restriction, provided that you do not Distribute the Modified Version.