clearspring - the widget network.

The Placement URL (known as the PUR) is the URL of the location that the widget is installed.  This is an import piece of data as the PUR is used to provide detailed domain level analytics. 

When using the container the PUR is captured automatically for the "seed" location and all installation, because the container is the first to load. Since the kernel is not the first to load, we are unable to determine the PUR in some cases. To maintain detailed analytics you must pass the PUR to the kernel URL as a query string; _cs_pur=[URL].  The value of _cs_pur must be valid (i.e., http://example.com is valid, but example.com will be ignored) and URL encoded.  For example when loading the kernel in AS3:

 var purVal:String = "http://www.example.com";
 var kernelUrl:String = 'http://widgets.clearspring.com/o/' + wid + 
				'/-/-TRK/1/lib.as3.swf?_cs_pur=' + escape(purVal);

When using the kernel's sharing services, the PUR is automatically set for all destination shared using the menu.  However, for the "seed" location you will need to set the PUR.  Setting the PUR for the "seed" location can be done by adding a Flash var to the embed code, for example:

 <object codebase="http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#
                    version=9,0,0,0" width="300" height="300">
   <param name="allowScriptAccess" value="sameDomain" />
   <param name="allowFullScreen" value="false" />
   <param name="movie" value="widget.swf" />
   <param name="quality" value="high" />
   <param name="bgcolor" value="#ffffff" />
   <param name="purVal" value="http%3A//www.example.com/" />
   <embed src="widgets.swf?purVal=http%3A//www.example.com/" quality="high" 
            bgcolor="#ffffff" width="300" height="250" allowScriptAccess="sameDomain" 
            allowFullScreen="false" type="application/x-shockwave-flash" 
            pluginspage="http://www.macromedia.com/go/getflashplayer" />
 </object>

Here your widget would use the Flash var purVal and set this as the value of _cs_pur for the kernel.  You should update your widget code to only send the _cs_pur when the purVal is set, for example:

 if(purVal != "") 
   kernelUrl = 'http://widgets.clearspring.com/o/' + wid + 
				'/-/-TRK/1/lib.as3.swf?_cs_pur=' + escape(purVal); 
 else 
   kernelUrl = 'http://widgets.clearspring.com/o/' + wid + '/-/-TRK/1/lib.as3.swf';

This will prevent setting the PUR to an empty value when nothing is passed in via the Flash var. 

If analytics are important to you and you are using the In-Widget APIs then you need to set the PUR for your seed location.  This will provide the best analytics.