I have tried the "add gadget by URL" option and only get a yellow box that tells me the gadget I have loaded is not valid and The gadget you added is not valid and lists the info below:
Unsupported feature: org.apache.shindig.common.xml.XmlException: The content of elements must consist of well-formed character data or markup. At: (4,57)
Unsupported feature: org.apache.shindig.common.xml.XmlException: The content of elements must consist of well-formed character data or markup. At: (4,57)