This is intended as a bullet-point guide to the concepts of copyright that someone new to programming will need to understand. An interest of mine is Free and Open Source Software (FOSS) so this guide includes points about the copyright context of that.

This is part of a planned set of postings - starting with the essentials and then exploring more detail for those who are interested. The intended titles are:

Short Version (i.e. this post)
Medium Version
Edge Cases
Myths and Misunderstandings

As the various parts are published I will amend this posting to provide links in the list above - so if you don't seen any links, then then others are still yet to come.

The Short Version

The Law

Bear in mind that this will involve some over-simplifications - the intention is to be brief but prepare an understanding before hitting the complexities.

Here are the dot points:

Copyright by now has a fairly uniform legal approach around the world.
By default, anything created has copyright automatically applied at the point of creation.
By default, copyright means that the creator "owns" the copyright and any and nearly all re-distribution is only legal if there is authorisation from that owner.
With private individuals, the "owner" is that private individual but with employees creating things in the course of their employment, the "owner" is usually the employer.
An owner can sell their copyright to another party who then "holds" the copyright.
Copyright does not apply to titles.
Copyright does apply to translations.
Copyright laws were mainly set up long before software became a major thing, but were adapted enough to explicitly cover software too.
For software, copyright is independent of whether you get to see the source code.
It is possible for the owner to embed a license statement in the copyrighted work that can grant various rights and freedoms to others, perhaps without requiring either contact or negotiation.
There is a broad set of of such licenses that are collectively known as providing "software freedom".
In practice, there are two independent organisations who provide guidance about such software licenses - the Free Software Foundation (FSF) and the Open Source Initiative (OSI).
While there are many, many variations on the software freedom licenses, they tend to fall into two main types - most commonly referred to as "copyleft" and "permissive".
Only a copyright owner can re-issue content with a different license.
Not all countries have a concept of "public domain" in their copyright laws, and those that do are not all the same about it.
Nearly all copyright laws specify a finite period of time for which copyright applies to a work.
But, many countries have repeatedly changed their copyright laws so as to keep pushing the point where copyright ceases for a work further and further into the future.
Somewhat similar to how titles are not copyrightable, many copyright laws allow for limited unauthorised publishing (e.g. of small extracts, or for specific purposes) but the terms, concepts and conditions vary quite a lot.

Those are the core principles that you need to know in order to understand the basics of copyright as a legal concept.

However, that leaves many possible complications, from interpretations of details, international variations, practical likelihoods, application to software, etc - those will instead be tackled in the "Medium" part.

Also, while most of that list is quite stark and bluntly stated, many misunderstandings and myths are often circulated - some of those will be tackled in the "Myths" part (e.g. suggestions that people other than the copyright owner can "re-license" a work).

Other Laws

As a quick aside:

The term "intellectual property" (or "IP") is somewhat made-up, so as to cover copyright, trademark and patent laws together;
Trademark laws vary greatly across countries, both legally and in practice;
Patent laws are about ideas and incidentally requires the ideas to be openly declared. By comparison, copyright is about the particular expressions - e.g. the text, pictures, videos, sounds, instructions.

Where both of those other "intellectual property" legal concepts have their own complications and variations.

Some other legal concepts that have intersections with software are:

contract law - particularly where one party is contracted by another to create a copyrightable work.
consumer law - where a copyrightable work is sold/given from a producer to a customer/user.
censorship laws - which might inhibit or prohibit the publishing of works independent of copyright
border laws - which might inhibit or prohibit the transit of works across national borders independent of copyright
(and perhaps many more such)

Other than being mentioned above, these other laws will not be covered by these notes. For one thing, they vary enormously from country to country.

Paying for things

Generally, copyright law doesn't say much about needing to pay for things. Instead it empowers the copyright owner to include payment requirements when authorising distribution and replication, such as via contracts and licenses.

How this plays out in practice varies enormously. For example, the replication might be physical (e.g. a paper book) and the payment physical (cash) with the bookseller returning a portion of the sale. Or it might all be virtual (downloaded software) and the payment virtual (credit card transaction online) direct to the producer (perhaps to get a valid unlock code to input to the software). Sometimes the model might be to not inhibit replication but to require allowing the copyright owner to "audit" the amount of usage and exact a corresponding payment. The mechanisms of such proprietary use of copyright are many and varied. Contracts, licenses and End User License Agreements (EULA) can be very complex.

The key is that unauthorised replication and distribution is a violation of copyright, independent of the exchange of funds.

Free and Open Source Software (FOSS)

There is a set of core concepts that are generally known as "the four freedoms": A program is free open source software if the program's users have the four essential freedoms:

freedom to run the program as you wish, for any purpose (freedom 0).
freedom to study how the program works, and change it so it does your computing as you wish (freedom 1). Access to the source code is a precondition for this.
freedom to redistribute copies so you can help others (freedom 2).
freedom to distribute copies of your modified versions to others (freedom 3). By doing this you can give the whole community a chance to benefit from your changes. Access to the source code is a precondition for this.

FOSS license statements, embedded in a work, effectively provide a pre-authorised negotiation, meaning neither creator nor adopter has to contact each other about the applicable conditions.

Note here that access to the source code is a mechanism to enable freedom.

By the way, you should ignore use of the term "commercial" software, as the software freedom concepts do not impede any parties from making financial (i.e. commercial) arrangements. The opposite of FOSS is proprietary where the defaults of copyright law apply, and all arrangements require an active negotiation.

The Two Main License Types

As said earlier, the major cleft among FOSS licenses are between two approaches. The distinction comes down to quite who is granted the most freedom:

with "copyleft" licenses the emphasis is on the end-user, ensuring that they are always passed the four freedoms;
with "permissive" licenses, the emphasis is on other developers/programmers, including allowing them to not pass on the four freedoms.

Those are distinct strategies with applicability to different situations. There is much discussion among the FOSS community about when each is the more suitable choice, or even whether it matters.

The thing that everyone agrees about, is that the copyright owner gets to choose the license to apply - essentially because copyright law enforces that privilege.

The Two Philosophies

About the two organisations who are the stewards of Free Open Source Software:

The Free Software Foundation came first, they set out the core ideas and also created the General Public License (probably the most important "copyleft" license).
The Open Source Initiative came later and, using the same four freedoms, emphasised the practical benefits of software freedom and also offered a service for approving specific licenses.

The two organisations have differing purposes and activities - complementary in effect. I recommend reading their own web sites for clarity - I see many inaccurate descriptions made about them by others.

My view is that you can mostly ignore any bickering between the Free Software and Open Source camps. They agree about most of what software freedom is all about. While their independent focus means they don't agree 100% - as a qualitative guess I would say the agreement is over 95% - indeed it is quite hard to find a license that one approves that the other does not.

Note they they also both support both "copyleft" and "permissive" licenses (and always have done)
Since this piece was initially published, I have published an article listing some of the differing license approvals by the FSF and OSI - see How many and of what nature are the license approval differences of the FSF and the OSI ?

Creative Commons

The innovation of using embedded licenses for software - to provide software freedom - was so successful that an effort arose to do something similar for non-software content. This led to the creation of a set known as Creative Commons licenses. These licenses enable authors of creative works to specify which rights they reserve and which rights they waive for the benefit of recipients or other creators.

This has also become sufficiently successful to now be quite frequently used for application to the documentation of software.

The core mechanism is the same as for software freedom licenses - of embedding a quotation of the license into the body of the copyrighted work. The distinction is about clarity:

of having a software license that talks about software concepts for applying to software
of having a content license that does not talk about software concepts for applying to things that are not-software.

Short Version Coda

Life is complex, and so the above opens the door for a lot of questions about the details. Those will be tackled in the next part.

Also, to reiterate, this "short" version is deliberately simplistic - and was left so, rather than litter it with footnotes and hyperlinks. Ideally I'd publish the full set all at once, but to avoid the overall delay of that, I will publish the parts only as and when I'm happy with them.

The reason I've written this, is because while I've seen a great many attempts at explaining Open Source Software or Free Software, nearly all presume a familiarity with copyright. So I wanted to try reversing that - to explain copyright first while placing FOSS in that context.

A Beginner's Guide to Copyright, Programming and Software - Short Version