String of all the URL parameters that were on the URL used to get to the current page. For example, if you add ?name=Samantha;age=24;eyes=blue to this URL you can see this in action. This string can be appended to a URL to pass parameter values on to another page.
URLs built this way are typically restricted in length, typically to 2048 characters. If you need more space than this, you will need to use an HTML form and =%QUERYPARAMS%=