Is playing a video from YouTube in a classroom an infringement?
This will depend upon the permissions that the creator of the video has granted any users, which will normally be expressed within some kind of licence, such as a Creative Commons licence. However, even if there is a licence to use content, reproduce and broadcast content etc associated with a video, it is important that the person who is granting the licence has the authority to grant it – i.e. they own the rights. In some case, people think that because they own a work, this allows them the right to both post it on social networking sites and also allow others to access it. In cases where they do not have this authority, any subsequent licences that they grant will be invalid contracts.