If you do a Google search for Ethics in Arts there are numerous articles that will give you all kinds of good advice about proper ethics in the Art world. Many of them are geared to the fine art world, but I'd like to talk a little about ethics on a smaller scale as it pertains to us as Etsy sellers and buyers.
Saying it is a smaller scale is a bit of a misnomer really. Etsy has grown by leaps and bounds and continues to do so. The internet and Etsy itself isn't really as big as you think it is. It is amazing how fast word of someone copying someone else's work gets around.
In the world of artists that I like to follow who happen to also be Etsy sellers there has been a rash of intellectual property theft as well as theft of images. I think using the word "copying" is really a little too benign in some cases. When the word "theft" is used, it really brings home the truth of what is really happening.
I've not been to an art school, or formally trained in any art. I consider myself to be mostly self taught. Being self taught means that you have to learn from somewhere. Tutorials, magazines, books, other artists. This is all well and good. Tutorials are made precisely for this reason! To teach others a skill. The problem comes into play when someone takes the item they made taught to them in a class or tutorial and begins selling them as their own work. Tutorials are meant to teach a skill to allow you to have a jumping off point to create your own work. To take a skill and use it in your own way to create your own artwork.
If you see the work of an artist you admire, and decide to duplicate that work and sell it as your own that is unethical and considered intellectual property theft. The same goes for taking an image you see on the internet and using it in your own publications without giving credit to the owner of the photo. It is theft.
I'm not sure I really understood the ethics of the art world when I decided to open my Etsy shop 4 years ago. Over the years I've seen artists defend their work and call out those that have stooped to unethical practices. I'm sure there are a lot of people out there who are ignorant as I once was. It is important to educate on this subject and to support other artists. It really goes back to the golden rule...do unto others as you'd have done unto you.