public void SubscribeTargetToSourceChanges(CloudBlob subscriber)
 {
     if (subscriber.CanContainExternalMetadata() == false)
     {
         throw new InvalidDataException("Subscriber candidate cannot contain metadata: " + subscriber.Name);
     }
     foreach (var source in CollectionContent.Where(src => src.IsInformationObjectSource))
     {
         SubscribeSupport.AddSubscriptionToObject(source.SourceLocation, subscriber.Name,
                                                  SubscribeSupport.SubscribeType_WebPageToSource);
     }
 }