Top best answers to the question «Can you copy and use youtube videos»
Copyright law protects the creative expression of ideas, encouraging people to produce new content… Therefore, you can copy a video idea from YouTube without infringing copyright, but you cannot use substantial clips without permission.
1 other answer
"You agree not to use the Website, including the YouTube Embeddable Player for any commercial use, without the prior written authorization of YouTube." This "commercial use" prohibition is reiterated in paragraph 5.E. So, what's a "commercial use?" Good question, and one which YouTube does not answer.