Company makes asp.net control that makes aspx page calls without refreshing the page.
Dart Communications - Visual Studio Component LabPretty much a rip off of the XmlHttp functionality of the MSXML control from old days, where you can go hit a URL, get the data, then use DHTML to render the results in some section of the page.
In the talk, the camera man basically describes the implementation just as I describe above -- control renders some javascript and uses MSXML XmlHttp request object.
The updating of the textbox without refresh is interesting, must use jscript and DHTML internally to do events like KeyPress.