Popularized by Snapchat, a story is a feature included on many popular social media networks. Rather than being grouped with other posts on timeline, stories are separate, temporary posts that are showcased in their section. Stories are presented in portrait orientation, being optimally viewed on a smartphone app, rather than a desktop browser. When a story is opened, the device transitions from story to story automatically. When users post a story on their profile, their circular profile icon shows a colored ring around it, indicating the story hasn't been viewed.
On Twitter, a story is more appropriately referred to as a Twitter Moment.