Stories app uses API of user's browser to get a media stream;
It's possible to upload photos or videos taken directly on mobile devices or from your computer;
Stories appear under activity feed and can be posted from a separate Story tab in activity post block;
It's possible to set stories expiration time in days;
Application optionally notifies users that their friend posted a story.
4.1.0 – initial release;
Question 1: Apple iPhone / iPad / iPod is used a lot – why is not safari supported here?
Currently Apple devices do not support playing WebM videos – this format is widely used on web and it was used on some devices when taking videos. There is a workaround – upload videos taken with device camera using Upload button.