What can be a resource shared through ArcGIS Online?

Sharing individual map layers or web maps through ArcGIS Online facilitates collaboration and enhances accessibility. ArcGIS Online is designed to allow users to share various types of resources, primarily to enable seamless interaction and utilization of GIS data across different platforms and users.

Web maps can include multiple layers, symbology, and other visualization components, making them an effective way to convey spatial information. Additionally, individual layers can be shared independently, allowing other users to access, visualize, and incorporate those layers into their own projects even without sharing the entire map. This flexibility supports a collaborative workflow, where users can contribute to and utilize each other's resources efficiently.

In contrast, the other options are too restrictive. While shapefiles and raw data or templates can be shared, they do not encompass the full range of resources available through ArcGIS Online, which is far more versatile. Server-based applications also represent a limited scope of the types of resources that can be shared, missing the interactive and collaborative elements that individual map layers and web maps provide.