All items in ArcGIS have a description. The description identifies the resource and allows you to find it when you search in ArcGIS for Desktop. However, items and their descriptions don't exclusively reside in ArcGIS for Desktop. An item and its description may be published to various sites that help people find and use GIS resources. A few of these options are described below.
ArcGIS Online—Allows people to share, find, and use GIS resources. As an ArcGIS user with Internet access, you can find content published by Esri, ArcGIS users, and other authoritative data providers as well as upload and share content of your own. If you publish services from ArcMap, the map's ArcGIS metadata is published with the data and becomes the service's metadata. If you share packages, the information you provide on the Item Description page on the Description tab or on the item's Properties dialog box is published with the item and will help others find it with a search.
Portal for ArcGIS—Brings together all the geographic information in your ArcGIS platform and shares it throughout your organization. The portal is a website and repository for GIS content deployed on your network. It allows you to create and share maps, search for GIS content in your organization, and send links to GIS applications hosted by the portal. As with ArcGIS Online, when you publish services, the map's metadata is published as the service's metadata. For packages, the information provided on the Item Description page in the ArcGIS metadata editor is transferred to the portal to describe the item and used when others search for items.
GeoPlatform.gov—A geoportal that provides access to United States federal, state, and local maps, data, and services as part of an e-government initiative. You can search and discover a wide variety of GIS resources, save your searches, and save maps that you build with any live services you find.
A geoportal—The Esri Geoportal Server allows you to provide a metadata catalog that lets people search and discover the GIS resources you have to share. A geoportal allows you to index and search an item's complete metadata as opposed to its brief item description. You might be able to contribute information about your resources to a community geoportal that is managed by another organization.