Alerts users can create public and private services, and may subscribe to any of them.
Users may be public or private entities, people interested in receiving alert messages from these entities or other people, and people interested in sending public or private
alert messages, to the community or a group.
Public entities, such as police and fire departments, may register as users in order to send alert messages to the community.
Private entities may register as users in order to send alert messages to the community or to private groups of users.
Any person may register as a user in order to subscribe to these public or private services, as well as to create services of their own.