coRank,the site lets you to add own Digg has just released some new features.Among the changes are the options to store local copies of Submissions and collaborative editing. The local copy feature allows you to store local ?cached? copies of any content that?s submitted, which essentially lets you create a permanent bookmarking tool for your own purposes. The collaborative editing tool introduces a level of wiki integration that lets users view the history of changed content, enabling a type of discussion to occur around submissions, and allow for user contributions to enhance submissions as well. Thoof is another bookmarking site that promotes this as a central feature.