Websites that allow children to easily create short stories and publish them online are called:

Websites that enable children to create and publish short stories online fall under the category of online story makers. These platforms are specifically designed to support creative writing and literacy development by providing user-friendly tools that allow young authors to compose stories, incorporate illustrations, and share their work with a broader audience. Online story makers often include appealing templates, prompts, and easy-to-navigate interfaces that can inspire children to engage with storytelling in an interactive way.

The other options do not pertain to platforms specifically designed for story creation. Social media is primarily focused on connecting people and sharing content rather than providing tools for story writing. PowerPoint is a presentation software that allows users to create slideshows, which is not directly related to story creation. Common Core refers to a set of educational standards that outline what students should know in math and English Language Arts but does not describe a specific tool for writing or publishing stories.