This is an archive related to a previous version of Esri Maps for SharePoint. If you need the current version go to http://doc.arcgis.com/en/maps-for-sharepoint/.
Signing in to ArcGIS Online with your Esri Global Account allows you to use the Map Center to open secure (non-public) web maps in the ArcGIS Map Web Part.
The Sign In dialog box appears.
Once you have signed in, you can use the Map Center to open secure (non-public) web maps in the Map Web Part.