I have added a new feature to my new service (http://copyto.co) which lets you have discussions on your public clipped pages. I just wanted to have your opinion about this functionality and whether you think if it would be useful. Thanks!
We have to delete public content that has been requested to be deleted by the copyright holders. In such a case the user will be notified about the infirigement and the possible removal of his content.
Copyright issue applies to all services that allow you to save a page, even Google would be guilty for caching. It is up to the user to judge for a copyright infringement before saving a page.