Unable to add a GeoRSS feed to Esri Maps for SharePoint.
"Error in reading the RSS feed."
The ArcGIS Map Web Part in SharePoint is built on the Microsoft Silverlight platform and uses the same URL access restrictions as a standalone Silverlight application. This includes requiring a clientaccesspolicy.xml or crossdomain.xml file to access remote data and cross-zone restrictions that prohibit an application in the Internet zone from accessing data in an elevated zone (Trusted or Local Intranet). These restrictions apply to both map services and GeoRSS feeds from remote servers when using Esri Maps for SharePoint.
In Internet Explorer, all RSS feed URLs are automatically placed in the 'Restricted sites' zone. In this case, it is more important to check the security zone of the RSS feed host. For example, if the RSS feed url is http://<rss_feed_host>/feeds/GeoRss.xml, check the security zone for just http://<rss_feed_host>.