Also, according to the picture below, it's valid to say you must link to the original article when you use it. Edit done.
Plagiarism is when you lie about someone's post, possibly without giving the source too.
Good Crediting - Fully linking to the whole source, and not make up stuff from the article including cherry picking and making up stuff from it.
Bad Crediting - Only saying my name, but failure of matching info; Lying about what an article, work, etc.
Lying and/or pretending you made it when that's not the case can be a huge problem. It's generally identity theft. Copy without permission, and lye about it. It's OK to Copy, without permission (Theft is when you remove the original), as long if you don't lie about it! Now be a good boy and stop being a Mule.
https://www.youtube.com/watch?v=dPtH2KPuQbs
Copyright though, isn't needed, that violates Free Culture.
Creative Commons - Without No D. and No.C doesn't.
Public Domain - Free Culture for sure.
Edit: I guess I should post this picture too:
