Not to be outdone by Instagram, Snapchat is announcing a new feature of its own today. While the news has recently been filled more with Instagram's copies of Snapchat's features, here's a chance for Snapchat to capture back some of the spotlight.
Custom Stories can be created about anything, and with any of your friends. So basically this lets groups of people contribute to the same Story. A Story is no longer a one-person affair. You decide who can add to the Story and who can view it.
You can also geofence a Custom Story to a specific location, and such Stories automatically disappear if none of the contributors have added things in the past 24 hours.