Google Developers Blog: AMP stories: Bringing visual storytelling to the open web
AMP stories are built on the technical infrastructure of AMP to provide a fast, beautiful experience on the mobile web. Just like any web page, a publisher hosts an AMP story HTML page on their site and can link to it from any other part of their site to drive discovery. And, as with all content in the AMP ecosystem, discovery platforms can employ techniques like pre-renderable pages, optimized video loading and caching to optimize delivery to the end user.
AMP stories aim to make the production of stories as easy as possible from a technical perspective. The format comes with preset but flexible layout templates, standardized UI controls, and components for sharing and adding follow-on content.