Hosting cross-domain Silverlight applications (XAP)
In the Silverlight world, there are two types of cross-domain things that may leave some banging their head against a wall for a while. The first involves making network-based calls (WebClient, HttpWebRequest, etc) to services hosted on a domain other than the one that is the site of origin for the XAP. This is solved by ensuring the service provider enables a clientaccesspolicy.xml file for their service. More information here: Cross Domain Policy Files with Silverlight.
NOTE: site of origin is...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.