As Instagram continues to carbon copy Snapchat, Snap looks to innovate its flagship app with unique twists on its iconic features. The latest addition is fully customized group Stories. These stories can be started by one user and then contributed to from their friends. Creators can control who has access to the content, which can also be geo-fenced. Stories disappear if no one has contributed to them in the past 24 hours, according to Snap. Snap, now public, has a loyal fanbase but has been struggling to add new users at a competitive rate. Instagram, owned by Facebook, has become a bitter rival to Snapchat, giving its larger user base virtually identical features. Stories, for example, was pioneered by Snap but quickly copied by Instagram.