Any problem with doing that? if credit is given to the OP? on a video sharing site. what is considered copyrighted? let say a video clip of a monkey eating hay, is that copyrighted? what other issues could have come up? wallpapers of celebrities are everywhere, can i download and post them on my wallpaper section?
I am sure I will be corrected by someone on this, but videos from sharing sites have been uploaded for use on that site. They are readily available for embedding, no problem, but you cannot take them and then put your logo on them because the owners didn't give them to you in that manner under your terms of service. If a video is infringing on copyright on You Tube, then that infringement is the same if you rehost it....still in violation. Wallpaper sites usually have a TOS and many times that says that they are available for redistribution with credit or fair use. The terms are usually on the site as to how you may use them or redistribute them.
well, what if there is no watermarking on the video? does the TOS of your site uphold if you put "we are not responsible for anything our user upload, but if you are the rightful owner, please contact us, balh blah blah and we will take it down?"
All videos are automatically copyrighted, regardless of the content. You cannot upload or display videos (or other content you didn't create) on your site without permission. No disclaimer will prevent you from being sued. Saying you are not responsible does not automatically get you off the hook. Offering to take down videos that are infringing is "hoping the copyright holder contacts you" instead of just suing you for damages. Youtube has a billion dollar lawsuit pending against them for user uploaded content. While youtube will allow you to embed videos, that doesn't mean you can upload copyrighted content and then embed the code. A site owner is ultimately responsible for all content they post on their site.