Whether it's copyrighted, in the public domain, a creative commons license, handed to you by a friend, found in a stairwell - if it is not yours, you should always cite it.
This is complicated because it includes not only individual items like a photograph or dataset but also any knowledge that you learned from somewhere.
**Not Common Knowledge
Intellectual Property refers to creations of the mind that are covered by various rights issued to the creator. These creations include things like:
As long as two individuals couldn't come up with the exact same item then it is probably covered or could be covered by intellectual property. So items like:
Are all unique creations of the mind. And they're all covered under a variety of rights. Some of the rights to creations are automatic - copyright for example is instantaneous. As soon as something is written down, it immediately has copyright and it's copyright can be violated. Other rights must be granted through an approval process. Trademarks and patents would fall into this group. These rights are issued on a first come basis. Whoever files the patent first with a country's patent office holds the exclusive rights.
The point of these exclusive rights isn't to grant creators special rights but to ensure that others are excluded from infringing upon the rights of creators. For copyright, these rights include: the right to display or perform your work, create copies or reproductions, create derivatives, and to sell any of all of these rights. Copyright wants the creator, and only the creator, to have these rights. For items with a patent, you want to stop anyone else but the patent holder from producing and selling a patented invention.
This is important because it allows all creators to profit from their creations and that encourages invention and creativity.
The exclusive rights given to Intellectual Properties are fairly straightforward in protecting those works. So how can anyone re-use and share portions of other people's works? By claiming the re-use as Fair Use.
Fair Use can be claimed in four instances:
But just because a copyrighted work is used for those four instances isn't enough. Fair Use also requires that there's an appropriate use of the copyrighted work. Whether something is truly Fair Use or not, is determined by these four requirements:
So if the use of the copyrighted work is commercial, you use too much of the copyrighted work, or the use has a negative impact on the copyrighted work's marketed value - it's not Fair Use. Even if the use was intended to be educational. And this decision of Fair or not is typical determined by court cases.
So you want to do a few things -
Copyright provides automatic and very exclusive rights to the creator. There's been a rising interest among creators to freely share their works in some ways. But there's a difficult caveat with copyright - if creators don't protect all the exclusive rights to their work at all times, they lose copyright entirely.
So creators that want to share their works, let others create copies or derivative works of their copyright materials, will actually forfeit their copyright entirely.
That's why Creative Commons was created. Creative Commons offers several copyright-based licenses that give creators the flexibility to keep some and release other exclusive rights. This allows creators to freely (and legally!) offer their works to be shared and altered without losing their copyright.
There are six types of Creative Commons Licenses that offer various rights. The one that is required for ALL licenses is attribution - you have to give credit to the original creator of the work. Beyond that are various options for how creators can allow their original work to be used, for what purpose, and how it can be shared.