What purpose do public groups serve in ArcGIS Online?

Public groups in ArcGIS Online are designed to facilitate sharing content and collaboration among users outside an organization. They allow users to create a space where individuals who are not part of the same organizational account can collaborate on projects, share maps, layers, and other content. This is particularly useful in situations where an organization wants to engage with community members, stakeholders, or the general public in the planning and decision-making process.

By utilizing public groups, organizations can extend their reach beyond internal users, allowing for greater participation and input from external audiences. This collaborative environment encourages knowledge sharing and can lead to more comprehensive and diverse data sets and insights.

The other purposes outlined in the options do not align with the functionality of public groups. While internal storage and user interface enhancements are necessary for managing data and usability, they do not specifically relate to the collaborative nature of public groups. Additionally, limiting access to users within an organization contradicts the fundamental purpose of public groups, which is to encourage openness and external collaboration.