The content becomes a sticker you can rotate and mark up when adding it to your story. You can only use snippets from public accounts, so if your friends are private, you can't forward their message to all your followers. The original poster will be labeled, too, so it's probably best not to pass along content from your shy buddies. Of course, if you mention who made the initial post, they can re-add that one to their story, and its stories all the way down...