This guide provides an introduction to using ArcGIS Online. ArcGIS Online enables the creation of web maps, web applications, and geospatial analysis projects to communicate with broad audiences related to spatial topics.
"ArcGIS Online is an online, collaborative web GIS that allows you to use, create, and share maps, scenes, apps, layers, analytics, and data." ArcGIS Online enables users to access geospatial layers from worldwide locations, create new content, and connect layers across the ArcGIS platform. In addition to web maps, applications are able to be created from configurable templates for enhanced user experience.
"In ArcGIS Online, a Web based, interactive map that allows you to display and query the layers on the map. A Web map contains one or more ArcGIS Server map services that are referenced to ArcGIS Online."