It is important to cite our sources in order to avoid plagiarism, because we should never intentionally take credit for the hard work of another writer, student or professional. It is just the same as the theft of a hard earned paycheck, or a family heirloom, that which has been tended to and protected. Also, when we plagiarize someone elses' ideas, we are advertising to the world that we are too lazy and/or creative to come up with our own ideas, learn and think for ourselves. I'm not sure how I would handle things if I learned that someone had taken my work and attempted to make others believe it was theirs, but I would be really upset. If it was in an academic setting, I would bring it to the attention of the dean of that school in order for it to be investigated, for a start. If it was done in a professional setting, and if someone plagiarized important field work, for instance, then I would seek legal recourse and possibly go to court over it. In the professional world, it is important to have copyrights put into place as soon as possible after a work is published, so that the author has this legal protection. In the case of websites that claim to legally own content written by someone else, I don't really think there is anything wrong with it per se, as a website is sometimes erected to make money, and therefore unless an author wants to submit a copyright request along with their post to the website, then the author should understand that a website such as youtube has the right to use the information however they see fit.