Copyright embed videos from Youtube. YouTube Terms of Service states that:

You also hereby grant each user of the Service a non-exclusive license to access your Content through the Service, and to use, reproduce, distribute, display and perform such Content as permitted through the functionality of the Service and under these Terms of Service. (YouTube TOS Section 6C- "Your Content and Conduct)

Hence, embedding a video from Youtube is not a infringment of a copyright, even if the video itself infringing a copyright. In that case, uploader to the Youtube is the only one who is responsible. You can investigate further and find about past court decisions about the issue. However, as a company we do not want to display video that violates copyrights or owner of the video is uncomfortable with us displaying it. Thus, if you are owner of a video that is displayed on our site and you are uncomfortable with it, you can follow two paths: