[WorldMaker]

If anything it's most closely akin to the old Netscape/Mozilla/Firefox Sidebar efforts:

http://edmullen.net/mozilla/moz_sidebar.php http://edmullen.net/mozilla/images/moz_shot_05.jpg

It's loading HTML (and maybe XAML, like Firefox allowed XUL) into a sidebar that may interact with the page it's pulled up alongside.